Raputsoane, Leroi (2025): Economic causation nexus and the minerals industry.
![]() |
PDF
MPRA_paper_124711.pdf Download (590kB) |
Abstract
This paper analyses the causality nexus between the minerals industry and selected macroeconomic indicators in South Africa. This is achieved by augmenting a Taylor1993 rule type central bank monetary policy reaction function with selected macroeconomic indicators and comparing the causality between the minerals industry and these macroeconomic indicators. The results provide evidence of a statistically significant unidirectional causality from commodity prices, foreign exchange rate and geopolitical risk to output of the minerals industry. The results have also shown a unidirectional causality from output of the minerals industry and government expenditure, or fiscal policy stance. The results further show a bidirectional causality between output of the minerals industry and monetary policy interest rate, foreign direct investment, financial market, business confidence, market uncertainty as well as external, or foreign, demand. The results, however, do not show the absence of causality, or causation, between output of the minerals industry and the selected macroeconomic indicators. Macroeconomic indicators are important for economic activity, hence policymakers should monitor developments in macroeconomic events to support economic growth as well as the minerals industry.
Item Type: | MPRA Paper |
---|---|
Original Title: | Economic causation nexus and the minerals industry |
Language: | English |
Keywords: | Economic causation, Minerals industry, Economic cycles |
Subjects: | C - Mathematical and Quantitative Methods > C1 - Econometric and Statistical Methods and Methodology: General > C10 - General E - Macroeconomics and Monetary Economics > E1 - General Aggregative Models > E10 - General E - Macroeconomics and Monetary Economics > E3 - Prices, Business Fluctuations, and Cycles > E30 - General L - Industrial Organization > L7 - Industry Studies: Primary Products and Construction > L72 - Mining, Extraction, and Refining: Other Nonrenewable Resources |
Item ID: | 124711 |
Depositing User: | Dr Leroi Raputsoane |
Date Deposited: | 09 May 2025 13:20 |
Last Modified: | 09 May 2025 13:20 |
References: | Abel, A. B. and Bernanke, B. S. (2001). Macroeconomics. Addison Wesley, Boston, Massachusetts, 4th edition. Adrian, T. (2018). An Overview of Inflation-Forecast Targeting. In Adrian, T., Laxton, D., and Obstfeld, M., editors, Advancing the Frontiers of Monetary Policy. International Monetary Fund (IMF), Washington D.C. Aiyar, M. S., Chen, M. J., Ebeke, C., Ebeke, M. C. H., Garcia-Saltos, M. R., Gudmundsson, T., Ilyina, M. A., Kangur, M. A., Kunaratskul, T., Rodriguez, M. S. L., et al. (2023a). Geoeconomic Fragmentation and the Future of Multilateralism. Staff Discussion Note, 2023/01. International Monetary Fund (IMF). Aiyar, S. and Ilyina, A. (2023). Geoeconomic Fragmentation: An Overview. In Aiyar, S., Presbitero, A., and Ruta, M., editors, Geoeconomic Fragmentation: The Economic Risks from a Fractured World Economy, pages 9–18. Centre for Economic Policy Research (CEPR) Press, London, United Kingdom. Aiyar, S., Presbitero, A., and Ruta, M. (2023b). Geoeconomic Fragmentation: The Economic Risks from a Fractured World Economy. Centre for Economic Policy Research (CEPR) Press, London, United Kingdom. Alfaro, L. (2023). Discussion of Geoeconomic Fragmentation and the Future of Multilateralism. In Aiyar, S., Presbitero, A., and Ruta, M., editors, Geoeconomic Fragmentation: The Economic Risks from a Fractured World Economy, pages 19–25. Centre for Economic Policy Research (CEPR) Press, London, United Kingdom. Arellano, C., Bai, Y., and Kehoe, P. J. (2019). Financial Frictions and Fluctuations in Volatility. Journal of Political Economy, 127(5):2049–2103. Atkinson, G. and Hamilton, K. (2003). Savings, Growth and the Resource Curse Hypothesis. World Development, 31(11):1793–1807. Auty, R. M. (2002). Sustaining Development in Mineral Economies: The Resource Curse Thesis. Routledge, Oxfordshire, England. Bacchetta, P. (2000). Capital Flows to Emerging Markets: Liberalization, Overshooting, and Volatility. In Edwards, S., editor, Capital Flows and the Emerging Economies: Theory, Evidence, and Controversies, pages 61–98. University of Chicago Press, Chicago, Illinois. Baxter, M. and King, R. G. (1999). Measuring Business Cycles: Approximate Band Pass Filters for Economic Time Series. Review of Economics and Statistics, 81(4):575–593. Bernanke, B. S. (1983). Irreversibility, Uncertainty, and Cyclical Investment. Quarterly Journal of Economics, 98(2):85–106. Bernanke, B. S. and Gertler, M. (1995). Inside the Black Box: The Credit Channel of Monetary Policy Transmission. Economic Review, 9(4):27–48. Bernanke, B. S. and Mishkin, F. S. (2007). Inflation Targeting: A New Framework for Monetary Policy? Journal of Economic Perspectives, 11(2):97–116. Blanchard, O. and Perotti, R. (2002). An Empirical Characterization of the Dynamic Effects of Changes in Government Spending and Taxes on Output. Quarterly Journal of Economics, 117(4):1329–1368. Blanchard, O. J. and Gali, J. (2007). The Macroeconomic Effects of Oil Shocks: Why are the 2000s So Different from the 1970s? Working Paper Series, 13368. National Bureau of Economic Research (NBER). Blanchard, O. J., Hall, R. E., and Hubbard, R. G. (1986). Market Structure and Macroeconomic Fluctuations. Brookings Papers on Economic Activity, 1986(2):285–338. Blanchard, O. J., LHuillier, J.-P., and Lorenzoni, G. (2013). News, Noise, and Fluctuations: An Empirical Exploration. American Economic Review, 103(7):3045–3070. Blanchard, O. J. and Quah, D. (1988). The Dynamic Effects of Aggregate Demand and Supply Disturbances. Working Papers Series, 2737. National Bureau of Economic Research (NBER). Bobasu, A., Geis, A., Quaglietti, L., and Ricci, M. (2020). Tracking Global Economic Uncertainty: Implications for Global Investment and Trade. Economic Bulletin, Issue 6. European Central Bank (ECB). Bosworth, B. P., Collins, S. M., and Reinhart, C. M. (1999). Capital Flows to Developing Economies: Implications for Saving and Investment. Brookings Papers on Economic Activity, 1999(1):143–180. Burns, A. F. and Mitchell, W. C. (1946). Measuring Business Cycles. National Bureau of Economic Research (NBER) Books, Cambridge, Massachusetts. Cagan, P. (1956). The Monetary Dynamics of Hyperinflation. In Friedman, M., editor, Studies in the Quantity Theory of Money, pages 25–117. University of Chicago Press, Chicago, Illinois. Caldara, D., Conlisk, S., Iacoviello, M., and Penn, M. (2024). Do Geopolitical Risks Raise or Lower Inflation? ASSA Meetings, 06 January. Federal Reserve Board of Governors (FRBG). Caldara, D. and Iacoviello, M. (2022). Measuring Geopolitical Risk. American Economic Review, 112(4):1194–1225. Calvo, G. A. and Mendoza, E. G. (2000). Contagion, Globalization, and the Volatility of Capital Flows. In Edwards, S., editor, Capital Flows and the Emerging Economies: Theory, Evidence, and Controversies, pages 41–42. University of Chicago Press, Chicago, Illinois. Canova, F. (2011). Methods for Applied Macroeconomic Research. Princeton University Press, Princeton, New Jersey. Cavallo, E. A. (2019). International Capital Flow Reversals. Working Paper Series, 1040. Inter-American Development Bank (IDB). Christiano, L., Eichenbaum, M., and Rebelo, S. (2011). When is the government spending multiplier large? Journal of Political Economy, 119(1):78–121. Christiano, L. J., Eichenbaum, M., and Evans, C. L. (1999). Monetary Policy Shocks: What Have We Learned and to What End? Handbook of macroeconomics, 1:65–148. Christiano, L. J., Eichenbaum, M., and Evans, C. L. (2005). Nominal Rigidities and the Dynamic Effects of a Shock to Monetary Policy. Journal of Political Economy, 113(1):1–45. Christiano, L. J. and Fitzgerald, T. J. (2003). The Band Pass Filter. International Economic Review, 44(2):435–465. Christiano, L. J., Motto, R., and Rostagno, M. (2014). Risk Shocks. American Economic Review, 104(1):27–65. Claessens, S. (2000). Capital Flows to Central and Eastern Europe and the Former Soviet Union. In Edwards, S., editor, Capital Flows and the Emerging Economies: Theory, Evidence, and Controversies, pages 197–246. University of Chicago Press, Chicago, Illinois. Clarida, R., Gali, J., and Gertler, M. (1999). The Science of Monetary Policy: A New Keynesian Perspective. Journal of economic literature, 37(4):1661–1707. Clarida, R., Gali, J., and Gertler, M. (2000). Monetary Policy Rules and Macroeconomic Stability: Evidence and Some Theory. Quarterly Journal of Economics, 115(1):147–180. Del Negro, M. and Schorfheide, F. (2011). Bayesian Macroeconometrics. Handbook of Bayesian Econometrics, 1(7):293–387. Devereux, M. B., Dong, W., and Tomlin, B. (2017). Importers and Exporters in Exchange Rate Pass-Through and Currency Invoicing. Journal of International Economics, 105:187–204. Diebold, F. X. (2007). Elements of Forecasting. Thomson South-Western,Westborough, Massachusetts, 2nd edition. Diebold, F. X. and Rudebusch, G. D. (1970). Measuring Business Cycles: A Modern Perspective. Review of Economics and Statistics, 78(1):67–77. Dornbusch, R. (1976). Expectations and Exchange Rate Dynamics. Journal of political Economy, 84(6):1161–1176. Dornbusch, R. (1987). Open Economy Macroeconomics: New Directions. Working Paper Series, 2372. National Bureau of Economic Research (NBER). Dornbusch, R. (1992). The Case for Trade Liberalization in Developing Countries. Journal of Economic Perspectives, 6(1):69–85. Eichengreen, B. and Irwin, D. A. (1995). Trade Blocs, Currency Blocs and the Reorientation of World Trade in the 1930s. Journal of International Economics, 38(1-2):1–24. European Central Bank (ECB) (2012). Stock Prices and Economic Growth. Monthly Bulletin, October. European Central Bank (ECB). European Central Bank (ECB) (2016). The Impact of Uncertainty on Activity in the Euro Area. Economic Bulletin, Issue 8. European Central Bank (ECB). Evans, C. and Kuttner, K. N. (1998). Can VARs Describe Monetary Policy? Working Paper Series, 9812. Federal Reserve Bank of Chicago. Farmer, R. E. (1999). The Macroeconomics of Self-Fulfilling Prophecies. MIT Press, Cambridge, Massachusetts, 2nd edition. Farmer, R. E. (2012). Confidence, Crashes and Animal Spirits. The Economic Journal, 122(559):155–172. Farmer, R. E. (2013). Animal Spirits, Financial Crises and Persistent Unemployment. The Economic Journal, 123(568):317–340. Feldstein, M. (2000). Aspects of Global Economic Integration: Outlook for the Future. Working Paper Series, 7899. National Bureau of Economic Research (NBER). Fisher, I. (1911). The Purchasing Power of Money, its Determination and Relation to Credit, Interest and Crises. Macmillan, New York City, New York. Fleming, M. J. (1962). Domestic Financial Policies Under Fixed and Under Floating Exchange Rates. Staff Papers, 9:369. International Monetary Fund (IMF). Frankel, J. A. (2008). An Explanation for Soaring Commodity Prices. VoxEU Columns, 25 March. Centre for Economic Policy Research (CEPR). Frankel, J. A. (2010). The Natural Resource Curse: A Survey. Working Paper Series, 15836. National Bureau of Economic Research (NBER). Frankel, J. A. (2012). The Natural Resource Curse: A Survey of Diagnoses and Some Prescriptions. Working Paper Series, RWP12-014. Harvard University Research. Frankel, J. A. and Romer, D. H. (1999). Does Trade Cause Growth? American Economic Review, 89(3):379–399. Friedman, M. (1957). A Theory of the Consumption Function. Princeton University Press, Chicago, Illinois. Friedman, M., Schwartz, A. J., et al. (1963). Money and Business Cycles. Bobbs-Merrill Company, Indianapolis, Indiana. Gali, J. (1992). How Well Does the IS-LM Model Fit Post War US Data? The Quarterly Journal of Economics, 107(2):709–738. Geweke, J. (1982). Measurement of Linear Dependence and Feedback Between Multiple Time Series. Journal of the American Statistical Association, 77(378):304–313. Giannone, D., Banbura, M., and Reichlin, L. (2010). Large Bayesian Vector Autoregressions. Journal of Applied Econometrics, 25(1):71–92. Giannone, D., Lenza, M., and Primiceri, G. E. (2015). Prior Selection for Vector Autoregressions. Review of Economics and Statistics, 97(2):436–451. Gieseck, A. and Rujin, S. (2020). The Impact of the Recent Spike in Uncertainty on Economic Activity in the Euro Area. Economic Bulletin, Issue 6. European Central Bank (ECB). Gilchrist, S., Sim, J. W., and Zakrajˇsek, E. (2014). Uncertainty, Financial Frictions, and Investment Dynamics. Working Paper Series, 20038. National Bureau of Economic Research (NBER). Gill, I. and Kose, M. A. (2024). 5 Major Risks Confronting the Global Economy in 2024. Articles, 17 January. Brookings Institution. Goldberg, L. S. and Tille, C. (2008). Vehicle Currency Use in International Trade. Journal of International Economics, 76(2):177–192. Goldsmith, R. W. (1959). Financial Structure and Development. In Goldsmith, R. W., editor, The Comparative Study of Economic Growth and Structure, pages 114–123. National Bureau of Economic Research (NBER), Cambridge, Massachusetts. Gopinath, G. (2015). The International Price System. Working Paper Series, 21646. National Bureau of Economic Research (NBER). Gopinath, G., Boz, E., Casas, C., Georgiadis, G., Le Mezo, H., Mehl, A., and Nguyen, T. (2022). Patterns of Invoicing Currency in Global Trade: New Evidence. Journal of International Economics, 136:103604. Gordon, R. J. (2007). The American Business Cycle: Continuity and Change, volume 25. University of Chicago Press, Chicago. Granger, C. W. J. (1969). Investigating Causal Relations by Econometric Models and Cross Spectral Methods. Econometrica, 37(3):424–438. Granger, C. W. J. (1980). Testing for causality: A personal viewpoint. Journal of Economic Dynamics and control, 2:329–352. Granger, C. W. J. (2004). Time Series Analysis, Cointegration, and Applications. American Economic Review, 94(3):421–425. Granger, C. W. J. and Newbold, P. (2014). Forecasting Economic Time Series. Academic press, Cambridge, Massachusetts, 2nd edition. Grossman, S. J. and Miller, M. H. (1988). Liquidity and Market Structure. Journal of Finance, 43(3):617–633. Gurley, J. G. and Shaw, E. S. (1967). Financial Structure and Economic Development. Economic development and cultural change, 15(3):257–268. Hall, M. (2024). How the Stock Market Affects GDP. Article, 24 November. Investopedia. Hamilton, J. D. (1994). Time Series Analysis. Princeton university press, Princeton, New Jersey, 1st edition. Hayes, A. (2024). Financial Markets: Role in the Economy, Importance, Types, and Examples. Article, 05 August. Investopedia. Heckman, J. J. (2008). Econometric Causality. International Statistical Review, 76(1):1–27. Hemming, R., Kell, M., and Mahfouz, S. (2002). The Effectiveness of Fiscal Policy in Stimulating Economic Activity: A Review of the Literature. Working Paper Series, 02/208. International Monetary Fund (IMF). Hodrick, R. and Prescott, E. C. (1997). Postwar U.S. Business Cycles: An Empirical Investigation. Journal of Money, Credit and Banking, 29(1):1–16. Hyndman, R. and Athanasopoulos, G. (2018). Forecasting: Principles and Practice. OTexts, Melbourne, 2nd edition. International Monetary Fund (IMF) (1994). The Recent Surge in Capital Flows to Developing Countries. World Economic Outlook, 14 October:48–64. International Monetary Fund (IMF). Jacks, D. S. (2013). From Boom to Bust: A Typology of Real Commodity Prices in the Long Run. Working Paper Series, 18874. National Bureau of Economic Research (NBER). Kadiyala, K. R. and Karlsson, S. (1997). Numerical Methods for Estimation and Inference in Bayesian VAR models. Journal of Applied Econometrics, 12(2):99–132. Keynes, J. M. (1936). The General Theory of Employment, Interest and Money. Palgrave Macmillan, London, United Kingdom. Koop, G. and Korobilis, D. (2010). Bayesian Multivariate Time Series Methods for Empirical Macroeconomics. Foundations and Trends in Econometrics, 3(4):267–358. Koop, G. M. (2013). Forecasting With Medium and Large Bayesian VARs. Journal of Applied Econometrics, 28(2):177–203. Kose, A. and Terrones, M. (2015). Uncertainty: How Bad Is It? In Collapse and Revival: Understanding Global Recessions and Recoveries, pages 121–128. International Monetary Fund (IMF), Washington, D.C. Kydland, F. E. and Prescott, E. C. (1990). Business Cycles: Real Facts and a Monetary Myth. Quarterly Review, 4:3–18. Federal Reserve Bank of Minneapolis. Labys, W. C., Achouch, A., and Terraza, M. (1999). Metal Prices and the Business Cycle. Resources Policy, 25(4):229–238. Labys, W. C. and Maizels, A. (1993). Commodity Price Fluctuations and Macroeconomic Adjustments in the Developed Economies. Journal of Policy Modeling, 15(3):335–352. Leamer, E. E. (1985). Sensitivity Analyses Would Help. American Economic Review, 75(3):308–313. Leland, H. E. (1968). Saving and uncertainty: The Precautionary Demand for Saving. The Quarterly Journal of Economics, 82(3):465–473. Levine, R. (1996). Stock Markets: A Spur to Economic Growth. Finance and Development, 33(001):7–10. Levine, R. and Zervos, S. (1998). Stock Markets, Banks, and Economic Growth. American Economic Review, 88(3):537–58. Litterman, R. (1984). Forecasting and Policy Analysis with Bayesian Vector Autoregression Models. Quarterly Review, Fall. Federal Reserve Bank of Minneapolis. Litterman, R. B. (1979). Techniques of Forecasting Using Vector Autoregressions. Working Paper Series, 115. Federal Reserve Bank of Minneapolis. Litterman, R. B. (1980). Bayesian Procedure for Forecasting with Vector Autoregressions. Working Paper Series, 274. Federal Reserve Bank of Minneapolis. Loungani, P. and Razin, A. (2001). How Beneficial is Foreign Direct Investment for Developing Countries? Finance and Development, 38(2):6–9. Lucas, R. E. (1972). Expectations and the Neutrality of Money. Journal of Economic Theory, 4(2):6–9. L¨utkepohl, H. (2005). New Introduction to Multiple Time Series Analysis. Springer Books, New York. Miller, M. H. (1998). Financial Markets and Economic Growth. Journal of Applied Corporate Finance, 11(3):8–15. Mise, E., Kimand, T., and Newbold, P. (2005). On Suboptimality of the Hodrick Prescott Filter at Time Series Endpoints. Journal of Macroeconomics, 27(1):53–67. Mishkin, F. S. (2021). The Economics of Money, Banking, and Financial Markets. Pearson Education, London, United Kingdom, 13th edition. Morgan Stanley Capital International (MSCI) (2014). Cyclical and Defensive Sectors. Indexes Methodology, June. Morgan Stanley Capital International (MSCI). Mundell, R. A. (1963). Capital Mobility and Stabilization Policy under Fixed and Flexible Exchange Rates. Canadian Journal of Economics and Political Science, 29(4):475–485. Muth, J. F. (1961). Rational Expectations and the Theory of Price Movements. Econometrica, 29(3):315–335. Obstfeld, M. (1994). Risk-Taking, Global Diversification and Growth. The American Economic Review, 84(5):1310–1329. Obstfeld, M. (2001). International Macroeconomics: Beyond the Mundell-Fleming Model. Working Paper Series, 8369(4):73–96. National Bureau of Economic Research (NBER). Obstfeld, M. and Rogoff, K. S. (1996). Foundations of International Macroeconomics. MIT press, Cambridge, Massachusetts. O’Hara, K. (2015). Bayesian Macroeconometrics in R. New York University Press, New York, 0.5.0 edition. Organisation for Economic Cooperation and Development (OECD) (2025). Inward FDI Flows by Partner Country, volume 10 February. Organisation for Economic Cooperation and Development (OECD). Pindyck, R. S. (1990). Irreversibility, Uncertainty, and Investment. Working Papers Series, 3307:151–155. National Bureau of Economic Research (NBER). Quah, D. (1988). Sources of Business Cycle Fluctuations: Comments. Macroeconomics Annual, 3:151–155. National Bureau of Economic Research (NBER). Ravn, M. O. and Uhlig, H. (2002). On Adjusting the Hodrick-Prescott Filter for the Frequency of Observations. Review of Economics and Statistics, 84(2):371–376. Romer, C. D. (1986). Is the Stabilization of the Postwar Economy a Figment of the Data? The American Economic Review, 76(3):314–334. Romer, C. D. (1993). Business Cycles. In Henderson, D. R., editor, The Fortune: Encyclopedia of Economics, volume 330.03 F745f. Warner Books. Rudebusch, G. D. (1998). Do Measures of Monetary Policy in a VAR Make Sense? International Economic Review, 39(4):907–931. Sargent, T. J. and Wallace, N. (1976). Rational Expectations And The Theory Of Economic Policy. Journal of Monetary economics, 2(2):169–183. Schwarz, G. (1978). Estimating the Dimension of a Model. Annals of Statistics, 6:461–464. Shapiro, M. D. (1987). Are Cyclical Fluctuations in Productivity Due More to Supply Shocks or Demand Shocks? Working Paper Series, 2589. National Bureau of Economic Research (NBER). Shapiro, M. D. and Watson, M. W. (1988). Sources of Business Cycle Fluctuations. Macroeconomics Annual, 3:111–156. National Bureau of Economic Research (NBER). Simon, J. L. (1970). The Concept of Causality in Economics. International Statistical Review, 23(2):226–254. Sims, C. A. (1972). Money, Income, and Causality. American Economic Review, 62(4):540–552. Sims, C. A. (1980). Macroeconomics and Reality. Journal of Economic Perspectives, 48(1):1–48. Sims, C. A. (1989). A Nine Variable Probabilistic Macroeconomic Forecasting Model. Discussion Paper, 14. Federal Reserve Bank of Minneapolis. Sims, C. A. and Uhlig, H. (1991). Understanding Unit Rooters: A Helicopter Tour. Econometrica, 59(6):1591–1599. Stock, J. H. and Watson, M. W. (1999). Business Cycle Fluctuations in US Macroeconomic Time Series. Handbook of Macroeconomics, 1(Part A):3–64. Stock, J. H. and Watson, M. W. (2001). Vector Autoregressions. Journal of Economic Perspectives, 15(4):101–115. Svensson, L. E. (1997). Inflation forecast targeting: Implementing and Monitoring Inflation Targets. European Economic Review, 41(6):1111–1146. Svensson, L. E. O. (2010). Inflation Targeting. In Friedman, B. M. and Woodford, M., editors, Handbook of Monetary Economics, volume 3, pages 1237–1302. Elsevier, Amsterdam, Netherlands. Svensson, L. E. O. and Woodford, M. (2004). Rational Expectations and the Theory of Economic Policy. In Bernanke, Ben S. and Woodford, Michael, editors, The Inflation-Targeting Debate, pages 19–92. University of Chicago Press, Chicago, Illinois. Taylor, J. B. (1993). Discretion Versus Policy Rules in Practice. Carnegie-Rochester Conference Series on Public Policy, 39:195–214. United Nations Industrial Development Organisation (UNIDO) (2023). International Yearbook of Industrial Statistics 2023. United Nations Industrial Development Organisation (UNIDO), Vienna, Austria. Uribe, M. and Schmitt-Grohe, S. (2017). Open Economy Macroeconomics. Princeton University Press, Princeton, New Jersey. Walsh, C. E. (2010). Monetary Theory and Policy. Massachusetts Institute of Technology (MIT) Press, Cambridge, Massachusetts, 3rd edition. Woodford, M. (2007). The Case For Forecast Targeting As A Monetary Policy Strategy. Journal of Economic Perspectives, 21(4):3–24. Woodford, M. (2011). Simple Analytics of the Government Expenditure Multiplier. American Economic Journal, 3(1):1–35. Woodford, M. and Walsh, C. E. (2005). Interest and Prices: Foundations of a Theory of Monetary Policy. Macroeconomic Dynamics, 9(3):462–468. |
URI: | https://mpra.ub.uni-muenchen.de/id/eprint/124711 |