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Volatility Modelling of Cryptocurrencies According to Different Investment Horizons: The Case of Bitcoin

Year 2025, Volume: 12 Issue: 2, 724 - 749, 30.06.2025
https://doi.org/10.30798/makuiibf.1609311

Abstract

In this study, the fractal structure, efficiency, and long memory features of Bitcoin are investigated according to different investment horizons. The study utilized daily returns from 01.01.2017 to 22.11.2023, applying the maximum overlap discrete wavelet transform, Rescaled Range (R/S) analysis, and volatility models. The analysis results revealed a deviation of Bitcoin returns from the average and a negative correlation, indicating a lack of permanent behaviour in the series. The analysis demonstrates the rejection of the efficient market hypothesis and reveals a chaotic structure in the Bitcoin market. Furthermore, we observed a hyperbolic rate of decrease in returns at long-term investment horizons due to information shocks. This indicates that past returns can predict future returns. This suggests that instead of the efficient market hypothesis, the fractal market hypothesis is valid due to the existence of recurring trends. Finally, we determined the most appropriate volatility models for Bitcoin. The analysis shows that information shocks in Bitcoin returns at medium- and long-term investment horizons decrease over time, and past returns can predict future returns. However, volatility and information shocks are transitory at short- and medium-term investment horizons but can vary. All analysis methods yield consistent and compatible results, suggesting their potential extension to other cryptocurrency markets beyond the Bitcoin market.

Ethical Statement

Ethics Committee approval was not required for this study. The authors declare that the study was conducted in accordance with research and publication ethics. The authors confirm that Artificial Intelligence tools were employed solely to enhance the clarity and fluency of the language. Following the use of these tools, the authors thoroughly reviewed and edited the content as needed and assume full responsibility for the final version of the published article. The authors declare that there are no financial conflicts of interest involving any institution, organization, or individual associated with this article. Additionally, there are no conflicts of interest among the authors. The authors affirm that they contributed equally to all processes of the research.

References

  • Açıkalın, S., & Sakınç, İ. (2022). Zayıf form etkinlik ve kripto para piyasası. Maliye ve Finans Yazıları, (117), 177–196. https://doi.org/10.33203/mfy.1084658
  • Al-Yahyaee, K. H., Mensi, W., & Yoon, S. M. (2018). Efficiency, multifractality, and the long-memory property of the Bitcoin market: A comparative analysis with stock, currency, and gold markets. Finance Research Letters, 27, 228–234. https://doi.org/10.1016/j.frl.2018.03.017
  • Assaf, A., Bhandari, A., Charif, H., & Demir, E. (2022). Multivariate long memory structure in the cryptocurrency market: The impact of COVID-19. International Review of Financial Analysis, 82, 102132. https://doi.org/10.1016/j.irfa.2022.102132
  • Baillie, R. T., Bollerslev, T., & Mikkelsen, H. O. (1996). Fractionally integrated generalized autoregressive conditional heteroskedasticity. Journal of Econometrics, 74(1), 3–30. https://doi.org/10.1016/S0304-4076(95)01749-6
  • Bariviera, A. F. (2017). The inefficiency of Bitcoin revisited: A dynamic approach. Economics Letters, 161, 1–4. https://doi.org/10.1016/j.econlet.2017.09.013
  • Bollerslev, T. (1986). Generalized autoregressive conditional heteroskedasticity. Journal of Econometrics, 31(3), 307–327. https://doi.org/10.1016/0304-4076(86)90063-1
  • Brooks, C. (2008). Introductory econometrics for finance. Cambridge University Press.
  • Brooks, C. (2019). Introductory econometrics for finance (4th ed.). Cambridge University Press.
  • Cao, G., He, L. Y., & Cao, J. (2018). Multifractal detrended analysis method and its application in financial markets. Springer.
  • Caporale, G. M., Gil-Alana, L., & Plastun, A. (2018). Persistence in the cryptocurrency market. Research in International Business and Finance, 46, 141–148. https://doi.org/10.1016/j.ribaf.2018.01.002
  • Celeste, V., Corbet, S., & Gurdgiev, C. (2020). Fractal dynamics and wavelet analysis: Deep volatility and return properties of Bitcoin, Ethereum, and Ripple. The Quarterly Review of Economics and Finance, 76, 310–324. https://doi.org/10.1016/j.qref.2019.09.011
  • Çelik, İ. (2020). Can Bitcoin be a stable investment? Financial Studies, 24(2 (88)), 19–36. https://hdl.handle.net/10419/231697
  • CoinMarketCap. (2023, December 25). Homepage. CoinMarketCap. https://coinmarketcap.com/
  • Crowley, P. M. (2007). A guide to wavelets for economists. Journal of Economic Surveys, 21(2), 207-267.
  • Davidson, J. (2004). Moment and memory properties of linear conditional heteroscedasticity models, and a new model. Journal of Business & Economic Statistics, 22(1), 16–29. https://doi.org/10.1198/073500103288619359
  • Davidson, R., & MacKinnon, J. G. (2004). Econometric theory and methods. Oxford University Press.
  • Ding, Z., & Granger, C. W. (1996). Modeling volatility persistence of speculative returns: A new approach. Journal of Econometrics, 73(1), 185–215. https://doi.org/10.1016/0304-4076(95)01737-2
  • Dyhrberg, A. H. (2016). Bitcoin, gold and the dollar–A GARCH volatility analysis. Finance Research Letters, 16, 85–92. https://doi.org/10.1016/j.frl.2015.10.008
  • Engle, R. (2002). Dynamic conditional correlation: A simple class of multivariate generalized autoregressive conditional heteroskedasticity models. Journal of business & economic statistics, 20(3), 339-350. https://doi.org/10.1198/073500102288618487
  • Eteman, V., & Işığıçok, E. (2022). Yüksek frekanslı kripto varlık oynaklığının uzun hafıza ve stokastik özelliklerinin FIGARCH modeli ile incelenmesi. Dicle Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi, 12(24), 284–310. https://doi.org/10.53092/duiibfd.1124966
  • Eyüboğlu, K., & Eyüboğlu, S. (2022). Bist ana sektör endekslerinde zayıf formda etkinliğin yapısal kırılmalı uzun hafiza modelleri ile analizi. Abant Sosyal Bilimler Dergisi, 22(2), 702-720. https://doi.org/10.11616/asbi.1097446
  • Fakhfekh, M., & Jeribi, A. (2020). Volatility dynamics of cryptocurrencies’ returns: Evidence from asymmetric and long memory GARCH models. Research in International Business and Finance, 51, 101075. https://doi.org/10.1016/j.ribaf.2019.101075
  • Gençay, R., Selçuk, F., & Whitcher, B. (2002). An introduction to wavelets and other filtering methods in finance and economics. Academic Press.
  • Hosking, J. R. M. (1981). Fractional differencing. Biometrika, 68(1), 165–176. https://doi.org/10.1093/biomet/68.1.165
  • Hurst, H. E. (1951). The long-term storage capacity of reservoirs. Transactions of the American Society of Civil Engineers, 116, 770–799. https://doi.org/10.1061/TACEAT.0006518. In, F., & Kim, S. (2012). An introduction to wavelet theory in finance: A wavelet multiscale approach. World Scientific.
  • Kasman, A., & Torun, E. (2007). Long memory in the Turkish stock market return and volatility. Central Bank Review, 7(2), 13–27.
  • Lillo, F., & Farmer, J. D. (2004). The long memory of the efficient market. Studies in Nonlinear Dynamics & Econometrics, 8(3), 1–33. https://doi.org/10.2202/1558-3708.1226
  • Liu, G., Yu, C. P., Shiu, S. N., & Shih, I. T. (2022). The efficient market hypothesis and the fractal market hypothesis: Interfluves, fusions, and evolutions. SAGE Open, 12(1), 1–8. https://doi.org/10.1177/21582440221082137
  • Lo, A. W. (1991). Long-term memory in stock market prices. Econometrica: Journal of the Econometric Society, 59(5), 1279–1313. https://doi.org/10.2307/2938368
  • Mallat, S. (1989). A wavelet tour of signal processing. Academic Press.
  • Mandelbrot, B. (1972). Statistical methodology for nonperiodic cycles: From the covariance to R/S analysis. In Annals of Economic and Social Measurement, Volume 1, Number 3 (pp. 259–290). NBER.
  • Mandelbrot, B. B. (1975). Limit theorems on the self-normalized range for weakly and strongly dependent processes. Zeitschrift für Wahrscheinlichkeitstheorie und Verwandte Gebiete, 31, 271–285. https://doi.org/10.1007/BF00532867
  • Mandelbrot, B. B., & Wallis, J. R. (1969). Computer experiments with fractional Gaussian noises: Averages and variances. Water Resources Research, 5(1), 228–241. https://doi.org/10.1029/WR005i001p00228
  • Mensi, W., Al-Yahyaee, K. H., & Kang, S. H. (2019). Structural breaks and double long memory of cryptocurrency prices: A comparative analysis from Bitcoin and Ethereum. Finance Research Letters, 29, 222–230. https://doi.org/10.1016/j.frl.2018.07.011
  • Mensi, W., Lee, Y. J., Al-Yahyaee, K. H., Sensoy, A., & Yoon, S. M. (2019). Intraday downward/upward multifractality and long memory in Bitcoin and Ethereum markets: An asymmetric multifractal detrended fluctuation analysis. Finance Research Letters, 31, 19–25. https://doi.org/10.1016/j.frl.2019.03.029
  • Mnif, E., & Jarboui, A. (2021). COVID-19, Bitcoin market efficiency, and herd behaviour. Review of Behavioral Finance, 13(1), 69–84. https://doi.org/10.1108/RBF-09-2020-0233
  • Moralı, T., & Uyar, U. (2018). Kıymetli metaller piyasasının fraktal analizi. Hitit Üniversitesi Sosyal Bilimler Enstitüsü Dergisi, 11(3), 2203–2218. https://doi.org/10.17218/hititsosbil.441151
  • Mulligan, R. F. (2004). Fractal analysis of highly volatile markets: An application to technology equities. The Quarterly Review of Economics And Finance, 44(1), 155-179, https://doi.org/10.1016/S1062-9769(03)00028-0
  • Nadarajah, S., & Chu, J. (2017). On the inefficiency of Bitcoin. Economics Letters, 150, 6–9. https://doi.org/10.1016/j.econlet.2016.10.033
  • Nakamoto, S. (2008). Bitcoin: A peer-to-peer electronic cash system. Manubot. Özdemir Yazgan, S. D. (2022). Kripto para piyasasında uzun hafıza ve fraktal dinamikler: Hibrit model yaklaşımı. In T. Ünkaracalar (Ed.), Finans, muhasebe ve iktisat alanlarında güncel araştırmalar-1 (pp. 1–19). Art Revisited.
  • Peters, E. E. (1994). Fractal market analysis: Applying chaos theory to investment and economics. Wiley.
  • Rachev, S. T., Mittnik, S., Fabozzi, F. J., Focardi, S. M., & Jasic, T. (2007). Financial econometrics: From basics to advanced modeling techniques. Wiley.
  • Sağlam Bezgin, M. (2023). Gelişmiş ve gelişmekte olan borsalar ile kripto varlık piyasasında Fraktal Piyasa Hipotezi’nin testi. Doğuş Üniversitesi Dergisi, 24(1), 81-91. https://doi.org/10.31671/doujournal.1101057
  • Tarı, R. (2014). Ekonometri. Umuttepe Yayınları. Kocaeli.
  • Tkacz, G. (2001). Estimating the fractional order of integration of interest rates using a wavelet OLS estimator. Studies in Nonlinear Dynamics & Econometrics, 5(1), 1–16. https://doi.org/10.2202/1558-3708.1068
  • Tsay, R. S. (2010). Analysis of financial time series (3rd ed.). John Wiley & Sons.
  • Urquhart, A. (2016). The inefficiency of Bitcoin. Economics Letters, 148, 80–82. https://doi.org/10.1016/j.econlet.2016.09.019
  • Uyar, U. (2019). Sistematik risk davranışında yatırım döngüsü: Wavelet analizi. Hacettepe Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi, 37(1), 135–168. https://doi.org/10.17065/huniibf.347775
  • Uyar, U., & Kangallı Uyar, S. (2021). Sermaye ve altın piyasaları arasındaki yayılım etkisi: Wavelet’e dayalı dinamik koşullu korelasyon yaklaşımı. In M. Ural & Ü. Aydın (Eds.), Finansal ekonometri uygulamaları: Kavram-teori-uygulama (pp. 309–335). Seçkin Yayıncılık. Zivot, E., & Wang, J. (2006). Modeling financial time series with S-Plus (2nd ed.). Springer.
  • Weron, R. (2002). Estimating long-range dependence: Finite sample properties and confidence intervals, Physica A, 312, 285-299.

Volatility Modelling of Cryptocurrencies According to Different Investment Horizons: The Case of Bitcoin

Year 2025, Volume: 12 Issue: 2, 724 - 749, 30.06.2025
https://doi.org/10.30798/makuiibf.1609311

Abstract

References

  • Açıkalın, S., & Sakınç, İ. (2022). Zayıf form etkinlik ve kripto para piyasası. Maliye ve Finans Yazıları, (117), 177–196. https://doi.org/10.33203/mfy.1084658
  • Al-Yahyaee, K. H., Mensi, W., & Yoon, S. M. (2018). Efficiency, multifractality, and the long-memory property of the Bitcoin market: A comparative analysis with stock, currency, and gold markets. Finance Research Letters, 27, 228–234. https://doi.org/10.1016/j.frl.2018.03.017
  • Assaf, A., Bhandari, A., Charif, H., & Demir, E. (2022). Multivariate long memory structure in the cryptocurrency market: The impact of COVID-19. International Review of Financial Analysis, 82, 102132. https://doi.org/10.1016/j.irfa.2022.102132
  • Baillie, R. T., Bollerslev, T., & Mikkelsen, H. O. (1996). Fractionally integrated generalized autoregressive conditional heteroskedasticity. Journal of Econometrics, 74(1), 3–30. https://doi.org/10.1016/S0304-4076(95)01749-6
  • Bariviera, A. F. (2017). The inefficiency of Bitcoin revisited: A dynamic approach. Economics Letters, 161, 1–4. https://doi.org/10.1016/j.econlet.2017.09.013
  • Bollerslev, T. (1986). Generalized autoregressive conditional heteroskedasticity. Journal of Econometrics, 31(3), 307–327. https://doi.org/10.1016/0304-4076(86)90063-1
  • Brooks, C. (2008). Introductory econometrics for finance. Cambridge University Press.
  • Brooks, C. (2019). Introductory econometrics for finance (4th ed.). Cambridge University Press.
  • Cao, G., He, L. Y., & Cao, J. (2018). Multifractal detrended analysis method and its application in financial markets. Springer.
  • Caporale, G. M., Gil-Alana, L., & Plastun, A. (2018). Persistence in the cryptocurrency market. Research in International Business and Finance, 46, 141–148. https://doi.org/10.1016/j.ribaf.2018.01.002
  • Celeste, V., Corbet, S., & Gurdgiev, C. (2020). Fractal dynamics and wavelet analysis: Deep volatility and return properties of Bitcoin, Ethereum, and Ripple. The Quarterly Review of Economics and Finance, 76, 310–324. https://doi.org/10.1016/j.qref.2019.09.011
  • Çelik, İ. (2020). Can Bitcoin be a stable investment? Financial Studies, 24(2 (88)), 19–36. https://hdl.handle.net/10419/231697
  • CoinMarketCap. (2023, December 25). Homepage. CoinMarketCap. https://coinmarketcap.com/
  • Crowley, P. M. (2007). A guide to wavelets for economists. Journal of Economic Surveys, 21(2), 207-267.
  • Davidson, J. (2004). Moment and memory properties of linear conditional heteroscedasticity models, and a new model. Journal of Business & Economic Statistics, 22(1), 16–29. https://doi.org/10.1198/073500103288619359
  • Davidson, R., & MacKinnon, J. G. (2004). Econometric theory and methods. Oxford University Press.
  • Ding, Z., & Granger, C. W. (1996). Modeling volatility persistence of speculative returns: A new approach. Journal of Econometrics, 73(1), 185–215. https://doi.org/10.1016/0304-4076(95)01737-2
  • Dyhrberg, A. H. (2016). Bitcoin, gold and the dollar–A GARCH volatility analysis. Finance Research Letters, 16, 85–92. https://doi.org/10.1016/j.frl.2015.10.008
  • Engle, R. (2002). Dynamic conditional correlation: A simple class of multivariate generalized autoregressive conditional heteroskedasticity models. Journal of business & economic statistics, 20(3), 339-350. https://doi.org/10.1198/073500102288618487
  • Eteman, V., & Işığıçok, E. (2022). Yüksek frekanslı kripto varlık oynaklığının uzun hafıza ve stokastik özelliklerinin FIGARCH modeli ile incelenmesi. Dicle Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi, 12(24), 284–310. https://doi.org/10.53092/duiibfd.1124966
  • Eyüboğlu, K., & Eyüboğlu, S. (2022). Bist ana sektör endekslerinde zayıf formda etkinliğin yapısal kırılmalı uzun hafiza modelleri ile analizi. Abant Sosyal Bilimler Dergisi, 22(2), 702-720. https://doi.org/10.11616/asbi.1097446
  • Fakhfekh, M., & Jeribi, A. (2020). Volatility dynamics of cryptocurrencies’ returns: Evidence from asymmetric and long memory GARCH models. Research in International Business and Finance, 51, 101075. https://doi.org/10.1016/j.ribaf.2019.101075
  • Gençay, R., Selçuk, F., & Whitcher, B. (2002). An introduction to wavelets and other filtering methods in finance and economics. Academic Press.
  • Hosking, J. R. M. (1981). Fractional differencing. Biometrika, 68(1), 165–176. https://doi.org/10.1093/biomet/68.1.165
  • Hurst, H. E. (1951). The long-term storage capacity of reservoirs. Transactions of the American Society of Civil Engineers, 116, 770–799. https://doi.org/10.1061/TACEAT.0006518. In, F., & Kim, S. (2012). An introduction to wavelet theory in finance: A wavelet multiscale approach. World Scientific.
  • Kasman, A., & Torun, E. (2007). Long memory in the Turkish stock market return and volatility. Central Bank Review, 7(2), 13–27.
  • Lillo, F., & Farmer, J. D. (2004). The long memory of the efficient market. Studies in Nonlinear Dynamics & Econometrics, 8(3), 1–33. https://doi.org/10.2202/1558-3708.1226
  • Liu, G., Yu, C. P., Shiu, S. N., & Shih, I. T. (2022). The efficient market hypothesis and the fractal market hypothesis: Interfluves, fusions, and evolutions. SAGE Open, 12(1), 1–8. https://doi.org/10.1177/21582440221082137
  • Lo, A. W. (1991). Long-term memory in stock market prices. Econometrica: Journal of the Econometric Society, 59(5), 1279–1313. https://doi.org/10.2307/2938368
  • Mallat, S. (1989). A wavelet tour of signal processing. Academic Press.
  • Mandelbrot, B. (1972). Statistical methodology for nonperiodic cycles: From the covariance to R/S analysis. In Annals of Economic and Social Measurement, Volume 1, Number 3 (pp. 259–290). NBER.
  • Mandelbrot, B. B. (1975). Limit theorems on the self-normalized range for weakly and strongly dependent processes. Zeitschrift für Wahrscheinlichkeitstheorie und Verwandte Gebiete, 31, 271–285. https://doi.org/10.1007/BF00532867
  • Mandelbrot, B. B., & Wallis, J. R. (1969). Computer experiments with fractional Gaussian noises: Averages and variances. Water Resources Research, 5(1), 228–241. https://doi.org/10.1029/WR005i001p00228
  • Mensi, W., Al-Yahyaee, K. H., & Kang, S. H. (2019). Structural breaks and double long memory of cryptocurrency prices: A comparative analysis from Bitcoin and Ethereum. Finance Research Letters, 29, 222–230. https://doi.org/10.1016/j.frl.2018.07.011
  • Mensi, W., Lee, Y. J., Al-Yahyaee, K. H., Sensoy, A., & Yoon, S. M. (2019). Intraday downward/upward multifractality and long memory in Bitcoin and Ethereum markets: An asymmetric multifractal detrended fluctuation analysis. Finance Research Letters, 31, 19–25. https://doi.org/10.1016/j.frl.2019.03.029
  • Mnif, E., & Jarboui, A. (2021). COVID-19, Bitcoin market efficiency, and herd behaviour. Review of Behavioral Finance, 13(1), 69–84. https://doi.org/10.1108/RBF-09-2020-0233
  • Moralı, T., & Uyar, U. (2018). Kıymetli metaller piyasasının fraktal analizi. Hitit Üniversitesi Sosyal Bilimler Enstitüsü Dergisi, 11(3), 2203–2218. https://doi.org/10.17218/hititsosbil.441151
  • Mulligan, R. F. (2004). Fractal analysis of highly volatile markets: An application to technology equities. The Quarterly Review of Economics And Finance, 44(1), 155-179, https://doi.org/10.1016/S1062-9769(03)00028-0
  • Nadarajah, S., & Chu, J. (2017). On the inefficiency of Bitcoin. Economics Letters, 150, 6–9. https://doi.org/10.1016/j.econlet.2016.10.033
  • Nakamoto, S. (2008). Bitcoin: A peer-to-peer electronic cash system. Manubot. Özdemir Yazgan, S. D. (2022). Kripto para piyasasında uzun hafıza ve fraktal dinamikler: Hibrit model yaklaşımı. In T. Ünkaracalar (Ed.), Finans, muhasebe ve iktisat alanlarında güncel araştırmalar-1 (pp. 1–19). Art Revisited.
  • Peters, E. E. (1994). Fractal market analysis: Applying chaos theory to investment and economics. Wiley.
  • Rachev, S. T., Mittnik, S., Fabozzi, F. J., Focardi, S. M., & Jasic, T. (2007). Financial econometrics: From basics to advanced modeling techniques. Wiley.
  • Sağlam Bezgin, M. (2023). Gelişmiş ve gelişmekte olan borsalar ile kripto varlık piyasasında Fraktal Piyasa Hipotezi’nin testi. Doğuş Üniversitesi Dergisi, 24(1), 81-91. https://doi.org/10.31671/doujournal.1101057
  • Tarı, R. (2014). Ekonometri. Umuttepe Yayınları. Kocaeli.
  • Tkacz, G. (2001). Estimating the fractional order of integration of interest rates using a wavelet OLS estimator. Studies in Nonlinear Dynamics & Econometrics, 5(1), 1–16. https://doi.org/10.2202/1558-3708.1068
  • Tsay, R. S. (2010). Analysis of financial time series (3rd ed.). John Wiley & Sons.
  • Urquhart, A. (2016). The inefficiency of Bitcoin. Economics Letters, 148, 80–82. https://doi.org/10.1016/j.econlet.2016.09.019
  • Uyar, U. (2019). Sistematik risk davranışında yatırım döngüsü: Wavelet analizi. Hacettepe Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi, 37(1), 135–168. https://doi.org/10.17065/huniibf.347775
  • Uyar, U., & Kangallı Uyar, S. (2021). Sermaye ve altın piyasaları arasındaki yayılım etkisi: Wavelet’e dayalı dinamik koşullu korelasyon yaklaşımı. In M. Ural & Ü. Aydın (Eds.), Finansal ekonometri uygulamaları: Kavram-teori-uygulama (pp. 309–335). Seçkin Yayıncılık. Zivot, E., & Wang, J. (2006). Modeling financial time series with S-Plus (2nd ed.). Springer.
  • Weron, R. (2002). Estimating long-range dependence: Finite sample properties and confidence intervals, Physica A, 312, 285-299.
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Details

Primary Language English
Subjects Behavioural Finance, Finance, Financial Econometrics, Financial Forecast and Modelling, Financial Risk Management, Investment and Portfolio Management
Journal Section Research Articles
Authors

Aslan Aydoğdu 0000-0001-9732-0614

Hafize Meder Çakır 0000-0002-3438-9611

Early Pub Date June 28, 2025
Publication Date June 30, 2025
Submission Date December 29, 2024
Acceptance Date June 3, 2025
Published in Issue Year 2025 Volume: 12 Issue: 2

Cite

APA Aydoğdu, A., & Meder Çakır, H. (2025). Volatility Modelling of Cryptocurrencies According to Different Investment Horizons: The Case of Bitcoin. Journal of Mehmet Akif Ersoy University Economics and Administrative Sciences Faculty, 12(2), 724-749. https://doi.org/10.30798/makuiibf.1609311

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