[1] Ahir, H., Bloom, N., Furceri, D. (2022). “The world uncertainty index”. NBER Working Paper, No. 29763, National Bureau of Economic Research. https://doi.org/10. 3386/w29763
[2] Ahn, K., Lee, D., Sohn, S., Yang, B. (2019). “Stock market uncertainty and economic fundamentals: An entropy-based approach”. Quantitative Finance, 19(7), 1151–1163. https://doi.org/10.1080/14697688.2019.1579922
[3] Ali, F., Khurram, M. U., Sensoy, A., Vo, X. V. (2024). “Green cryptocurrencies and portfolio diversification in the era of greener paths”. Renewable & Sustainable Energy Reviews, 191, 114137. https://doi.org/10.1016/j.rser.2023.114137
[4] Amirteimoori, A. (2024). “Efficiency analysis in two-stage data envelopment analysis with shared resources and undesirable outputs: An application in the banking sector”. International Transactions in Operational Research. https://doi.org/10.1111/itor. 13454
[5] Arabmaldar, A., Jablonský, J., Hosseinzadeh Saljooghi, F. (2017). “A new robust DEA model and super-efficiency measure”. Optimization, 66(5), 723–736. https://doi.org/10.1080/02331934.2017.1295047
[6] Araya-Sassi, C., Miranda, P. A., Paredes-Belmar, G. (2018). “Lagrangian relaxation for an inventory location problem with periodic inventory control and stochastic capacity constraints”. Mathematical Problems in Engineering, 2018, 1–27. https://doi.org/10. 1155/2018/8237925
[7] Avellán, G., González-Astudillo, M., Salcedo Cruz, J. J. (2022). “Measuring uncertainty: A streamlined application for the Ecuadorian economy”. Empirical Economics, 62(4), 1517–1542. https://doi.org/10.1007/s00181-021-02069-5
[8] Babaei, S., Sepehri, M. M., Babaei, E. (2015). “Multi-objective portfolio optimization considering the dependence structure of asset returns”. European Journal of Operational Research, 244(2), 525–539. https://doi.org/10.1016/j.ejor.2015.01.025
[9] Ben-Tal, A., Nemirovski, A. (2001). “Lectures on modern convex optimization: Analysis, Algorithms, and Engineering Applications”. Society for Industrial and Applied Mathematics. https://doi.org/10.1137/1.9780898718829
[10] Bertsimas, D., Sim, M. (2004). “The price of robustness”. Operations Research, 52(1), 35–53. https://doi.org/10.1287/opre.1030.0065
[11] Best, M. J., Grauer, R. R. (1991). “On the sensitivity of mean-variance-efficient portfolios to changes in asset means: some analytical and computational results”. The Review of Financial Studies, 4(2), 315–342. https://doi.org/10.1093/rfs/4.2.315
[12] Boussofiane, A., Dyson, R. G., Thanassoulis, E. (1991). “Applied data envelopment analysis”. European Journal of Operational Research, 52(1), 1–15. https://doi.org/10. 1016/0377-2217(91)90331-O
[13] Bouteska, A., Abedin, M. Z., Hajek, P., Yuan, K. (2024). “Cryptocurrency price forecasting – a comparative analysis of ensemble learning and deep learning methods”. International Review of Financial Analysis, 92, 103055. https://doi.org/10.1016/j.irfa. 2023.103055
[14] Brini, A., Lenz, J. (2024). “Pricing cryptocurrency options with machine learning regression for handling market volatility”. Economic Modelling, 136, 106752. https://doi. org/10.1016/j.econmod.2024.106752
[15] Burggraf, T. (2021). “Beyond risk parity – a machine learning-based hierarchical risk parity approach on cryptocurrencies”. Finance Research Letters, 38, 101523. https: //doi.org/10.1016/j.frl.2020.101523
[16] Burkaltseva, D., Niyazbekova, S., Borsch, L., Jallal, M. A. K., Apatova, N., Nurpeisova, A., Semenov, A., Zhansagimova, A. (2021). “Methodological foundations of the risk of the stock markets of developed and developing countries in the conditions of the crisis”. Journal of Risk and Financial Management, 15(1), 3. https://doi.org/10.3390/ jrfm15010003
[17] Chang, T.-S., Tone, K., Wu, C.-H. (2021). “Nested dynamic network data envelopment analysis models with infinitely many decision making units for portfolio evaluation”. European Journal of Operational Research, 291(2), 766–781. https://doi.org/10. 1016/j.ejor.2020.09.044
[18] Charnes, A., Cooper, W. W., Rhodes, E. (1978). “Measuring the efficiency of decision making units”. European Journal of Operational Research, 2(6), 429–444. https://doi. org/10.1016/0377-2217(78)90138-8
[19] Choi, H.-S., Min, D. (2017). “Efficiency of well-diversified portfolios: Evidence from data envelopment analysis”. Omega, 73, 104–113. https://doi.org/10.1016/j.omega. 2016.12.008
[20] Chou, J.-S., Chen, K.-E. (2024). “Optimizing investment portfolios with a sequential ensemble of decision tree-based models and the FBI algorithm for efficient financial analysis”. Applied Soft Computing, 158, 111550. https://doi.org/10.1016/j.asoc. 2024.111550
[21] Chuliá, H., Guillén, M., Uribe, J. M. (2017). “Measuring uncertainty in the stock market”. International Review of Economics & Finance, 48, 18–33. https://doi.org/10.1016/ j.iref.2016.11.003
[22] Cook, W. D., Seiford, L. M. (2009). “Data envelopment analysis (DEA) – thirty years on”. European Journal of Operational Research, 192(1), 1–17. https://doi.org/10. 1016/j.ejor.2008.01.032
[23] Cook, W. D., Zhu, J. (Eds.). (2014). “Data envelopment analysis: A handbook of modeling internal structure and network”. Springer, New York. https://doi.org/10.1007/ 978-1-4899-8068-7
[24] Doshi, H., Kumar, P., Yerramilli, V. (2018). “Uncertainty, capital investment, and risk management”. Management Science, 64(12), 5769–5786. https://doi.org/10.1287/ mnsc.2017.2815
[25] El Kharrim, M. (2023). “Multi-period fuzzy portfolio optimization model subject to real constraints”. EURO Journal on Decision Processes, 11, 100041. https://doi.org/10.1016/j.ejdp.2023.100041
[26] Escobari, D., Jafarinejad, M. (2019). “Investors’ uncertainty and stock market risk”. Journal of Behavioral Finance, 20(3), 304–315. https://doi.org/10.1080/15427560. 2018.1506787
[27] Fang, C., Chi, M., Fan, S., Choi, T.-M. (2024). “Who should invest in blockchain technology under different pricing models in supply chains?”. European Journal of Operational Research, 319(3), 777–792. https://doi.org/10.1016/j.ejor.2024.07.006
[28] Färe, R., Grosskopf, S. (2000). “Network DEA”. Socio-Economic Planning Sciences, 34(1), 35–49. https://doi.org/10.1016/S0038-0121(99)00012-9
[29] Fisher, M. L. (1981). “The Lagrangian relaxation method for solving integer programming problems”. Management Science, 27(1), 1–18. https://doi.org/10.1287/mnsc.27. 1.1
[30] Fukuyama, H., Tsionas, M., Tan, Y. (2023). “Dynamic network data envelopment analysis with a sequential structure and behavioural-causal analysis: application to the Chinese banking industry”. European Journal of Operational Research, 307(3), 1360–1373. https://doi.org/10.1016/j.ejor.2022.09.028
[31] Goel, A., Sharma, A., Mehra, A. (2018). “Index tracking and enhanced indexing using mixed conditional value-at-risk”. Journal of Computational and Applied Mathematics, 335, 361–380. https://doi.org/10.1016/j.cam.2017.12.015
[32] Goel, A., Sharma, A., Mehra, A. (2019). “Robust optimization of mixed CVaR STARR ratio using copulas”. Journal of Computational and Applied Mathematics, 347, 62–83. https://doi.org/10.1016/j.cam.2018.08.001
[33] Golnari, A., Komeili, M. H., Azizi, Z. (2024). “Probabilistic deep learning and transfer learning for robust cryptocurrency price prediction”. Expert Systems with Applications, 255, 124404. https://doi.org/10.1016/j.eswa.2024.124404
[34] Gong, X., Yu, C., Min, L., Ge, Z. (2021). “Regret theory-based fuzzy multi-objective portfolio selection model involving DEA cross-efficiency and higher moments”. Applied Soft Computing, 100, 106958. https://doi.org/10.1016/j.asoc.2020.106958
[35] Guignard, M. (2003). “Lagrangean relaxation”. TOP, 11(2), 151–200. https://doi. org/10.1007/BF02579036
[36] James, N., Menzies, M. (2022). “Collective correlations, dynamics, and behavioural inconsistencies of the cryptocurrency market over time”. Nonlinear Dynamics. https://doi.org/10.1007/s11071-021-07166-9
[37] Jiang, W., Zhu, P., Korkmaz, A. G., Zhou, H. (2024). “The asymmetric nexus between the cryptocurrency market and the carbon market: evidence from the quantile-on-quantile method”. Journal of Climate Finance, 7, 100037. https://doi.org/10.1016/ j.jclimf.2024.100037
[38] Kakouris, I., Rustem, B. (2014). “Robust portfolio optimization with copulas”. European Journal of Operational Research, 235(1), 28–37. https://doi.org/10.1016/j.ejor. 2013.12.022
[39] Kao, C. (2018). “A classification of slacks-based efficiency measures in network data envelopment analysis with an analysis of the properties possessed”. European Journal of Operational Research, 270(3), 1109–1121. https://doi.org/10.1016/j.ejor.2018. 04.036
[40] Kao, C., Hwang, S.-N. (2008). “Efficiency decomposition in two-stage data envelopment analysis: an application to non-life insurance companies in Taiwan”. European Journal of Operational Research, 185(1), 418–429. https://doi.org/10.1016/j.ejor.2006. 11.041
[41] Katsiampa, P. (2019). “An empirical investigation of volatility dynamics in the cryptocurrency market”. Research in International Business and Finance, 50, 322–335. https: //doi.org/10.1016/j.ribaf.2019.06.004
[42] Katsiampa, P., Corbet, S., Lucey, B. (2019). “Volatility spillover effects in leading cryptocurrencies: a BEKK-MGARCH analysis”. Finance Research Letters, 29, 68–74. https://doi.org/10.1016/j.frl.2019.03.009
[43] Konno, H., Yamazaki, H. (1991). “Mean-absolute deviation portfolio optimization model and its applications to Tokyo stock market”. Management Science, 37(5), 519–531. https://doi.org/10.1287/mnsc.37.5.519
[44] Larni-Fooeik, A., Sadjadi, S. J., Mohammadi, E. (2024). “Stochastic portfolio optimization: a regret-based approach on volatility risk measures: An empirical evidence from the New York stock market”. PLOS ONE, 19(4), e0299699. https://doi.org/10.1371/ journal.pone.0299699
[45] Li, B., Teo, K. L. (2021). “Portfolio optimization in real financial markets with both uncertainty and randomness”. Applied Mathematical Modelling, 100, 125–137. https: //doi.org/10.1016/j.apm.2021.08.006
[46] Lin, R., Ding, L., Li, Z. (2024). “Efficiency evaluation and productivity analysis of complex electric power systems in China: A directional slacks-based network data envelopment analysis approach”. International Journal of Electrical Power & Energy Systems, 156, 109751. https://doi.org/10.1016/j.ijepes.2023.109751
[47] Liu, H., Zhang, R., Zhou, L., Li, A. (2023). “Evaluating the financial performance of companies from the perspective of fund procurement and application: new strategy cross efficiency network data envelopment analysis models”. Energy, 269, 126739. https:// doi.org/10.1016/j.energy.2023.126739
[48] Lotfi, R., Ghaboulian Zare, S., Gharehbaghi, A., Nazari, S., Weber, G.-W. (2023). “Robust optimization for energy-aware cryptocurrency farm location with renewable energy”. Computers & Industrial Engineering, 177, 109009. https://doi.org/10.1016/ j.cie.2023.109009
[49] Luan, D., Wang, C., Wu, Z., Xia, Z. (2021). “Two-stage robust optimization model for uncertainty investment portfolio problems”. Journal of Mathematics, 2021, 3087066. https://doi.org/10.1155/2021/3087066
[50] Ma, Y., Wang, Y., Wang, W., Zhang, C. (2023). “Prediction-based mean–variance portfolios with risk budgeting based on neural networks”. Expert Systems with Applications, 230, 120638. https://doi.org/10.1016/j.eswa.2023.120638
[51] Markowitz, H. (1952). “Portfolio selection”. The Journal of Finance, 7(1), 77–91. https: //doi.org/10.2307/2975974
[52] Markowitz, H. M. (1959). Portfolio selection: Efficient diversification of investments. John Wiley & Sons, New York.
[53] Mulvey, J. M., Vanderbei, R. J., Zenios, S. A. (1995). “Robust optimization of large-scale systems”. Operations Research, 43(2), 264–281. https://doi.org/10.1287/ opre.43.2.264
[54] Nakamoto, S. (2008). “Bitcoin: A peer-to-peer electronic cash system”. Available at https://bitcoin.org/bitcoin.pdf
[55] Nguyen, A. P. N., Mai, T. T., Bezbradica, M., Crane, M. (2023). “Volatility and returns connectedness in cryptocurrency markets: insights from graph-based methods”. Physica A: Statistical Mechanics and its Applications, 632, 129349. https://doi.org/10. 1016/j.physa.2023.129349
[56] Oyewola, D. O., Dada, E. G., Ndunagu, J. N. (2022). “A novel hybrid walk-forward ensemble optimization for time series cryptocurrency prediction”. Heliyon, 8(11), e11862. https://doi.org/10.1016/j.heliyon.2022.e11862
[57] Peykani, P., Mohammadi, E., Jabbarzadeh, A., Rostamy-Malkhalifeh, M., Pishvaee, M. S. (2020). “A novel two-phase robust portfolio selection and optimization approach under uncertainty: a case study of Tehran Stock Exchange”. PLOS ONE, 15(10), e0239810. https://doi.org/10.1371/journal.pone.0239810
[58] Ranković, V., Drenovak, M., Urosevic, B., Jelic, R. (2016). “Mean-univariate GARCH VaR portfolio optimization: actual portfolio approach”. Computers & Operations Research, 72, 83–92. https://doi.org/10.1016/j.cor.2016.01.014
[59] Sadeghi, J., Begen, M. A., Ødegaard, F. (2023). “Refined bounds for the non-Archimedean ϵ in DEA”. Computers & Operations Research, 154, 106163. https://doi.org/10. 1016/j.cor.2023.106163
[60] Siddique, M. A., Nobanee, H., Karim, S., Naz, F. (2023). “Do green financial markets offset the risk of cryptocurrencies and carbon markets?” International Review of Economics & Finance, 86, 822–833. https://doi.org/10.1016/j.iref.2023.04.005
[61] Soyster, A. L. (1973). “Convex programming with set-inclusive constraints and applications to inexact linear programming”. Operations Research, 21(5), 1154–1157. https: //doi.org/10.1287/opre.21.5.1154
[62] Umar, M., Rizvi, S. K. A., Naqvi, B. (2021). “Dance with the devil? The nexus of fourth industrial revolution, technological financial products and volatility spillovers in global financial system”. Technological Forecasting and Social Change, 163, 120450. https: //doi.org/10.1016/j.techfore.2020.120450
[63] Vaseei, M., Daneshmand-Mehr, M., Bazrafshan, M., Kanafi, A. G. (2023). “A network data envelopment analysis to evaluate the performance of a sustainable supply chain using bootstrap simulation”. Journal of Engineering Research, 12(4), 904–915. https://doi. org/10.1016/j.jer.2023.10.003
[64] Vikas, V., Bansal, R. (2019). “Efficiency evaluation of Indian oil and gas sector: data envelopment analysis”. International Journal of Emerging Markets, 14(2), 362–378. https: //doi.org/10.1108/ijoem-01-2018-0016
[65] Wolsey, L. A. (2020). Integer Programming, 2nd ed. John Wiley & Sons, Hoboken, NJ. https://doi.org/10.1002/9781119606475
[66] Wu, Z., Sun, K. (2023). “Distributionally robust optimization with Wasserstein metric for multi-period portfolio selection under uncertainty”. Applied Mathematical Modelling, 117, 513–528. https://doi.org/10.1016/j.apm.2022.12.037
[67] Yan, L., Mirza, N., Umar, M. (2022). “The cryptocurrency uncertainties and investment transitions: evidence from high and low carbon energy funds in China”. Technological Forecasting and Social Change, 175, 121326. https://doi.org/10.1016/j. techfore.2021.121326
[68] Zhang, R., Wei, Q., Li, A., Ren, L. (2022). “Measuring efficiency and technology inequality of China’s electricity generation and transmission system: a new approach of network data envelopment analysis prospect cross-efficiency models”. Energy, 246, 123274. https://doi.org/10.1016/j.energy.2022.123274
[69] Zhu, B., Zhang, T. (2021). “Long-term wealth growth portfolio allocation under parameter uncertainty: a non-conservative robust approach”. The North American Journal of Economics and Finance, 57, 101432. https://doi.org/10.1016/j.najef.2021. 101432