1.Abbasian, M. 2012. Study of joint distribution functions in hydrology using copula. (BS Thesis) Power and Water University of Technology, Tehran, Iran, 92p. (In Persian)
2.Abbasian, M., Jalali, S., and Mousavi Nadoushani, S.S. 2015. Multivariate flood frequency analysis using copula with parametric and nonparametric marginal distribution function. MJCE. 14: 4. 81-92. (In Persian)
3.Amirataee, B., Montaseri, M., and Rezaie, H. 2018. Regional analysis and derivation of copula-based drought Severity-Area-Frequency curve in Lake Urmia basin, Iran. J. Environ. Manage. 206: 134-144.
4.Ayantobo, O.O., Li, Y., Song, S., Javed, T., and Yao, N. 2018. Probabilistic modelling of drought events in China via 2-dimensional joint copula. J. Hydrol. 559: 373-391.
5.Dracup, J.A., Lee, K.S., and Paulson, E.G. 1980a. On the statistical characteristics of drought events. Water Resour. Res. 16: 2. 289-296.
6.Dracup, J.A., Lee, K.S., and Paulson, E.G. 1980b. On the definition of droughts. Water Resour. Res. 16: 2.297-302.
7.Farrokhnia, A., and Morid, S. 2007. Drought severity and duration analysis by using copulas. 4th National Congress on Civil Engineering. University of Tehran, Tehran, Iran. (In Persian)
8.Ghorbani, M. 2013. Comparison between using of the bivariate generalized pareto distribution and the copula functions approach in low-flow indices analysis. (M.Sc. Thesis) Shahid Beheshti University, Tehran, Iran, 106p. (In Persian)
9.Heim, R.R. 2002. A review of twentieth-century drought indices used in the United States. Bull. Amer. Meteor. Soc. 83: 8. 1149-1166.
10.Hisdal, H., Tallaksen, L.M., Clausen, B., Peters, E., and Gustard, A. 2004. Hydrological drought characteristics. P 139-198, In: Tallaksen, L., van Lanen, H.A.J. (Eds.), Hydrological Drought. Elsevier Science B.V., Amsterdam, the Netherlands.
11.Jakubowski, W. 2006. An application of the bivariate generalized pareto distribution for the probabilities of low flow extremes estimation. Hydrol. Earth Syst. Sci. Discussions. 3: 859-893.
12.McKee, T.B., Doesken, N.J., and Kleist, J. 1993. The relationship of drought frequency and duration to time scales, paper presented at Eighth Conference on Applied Climatology. Am. Meteorol. Soc., Anaheim, CA.
13.Mirabbasi, R., Fakheri-Fard, A., and Dinpazhoh, Y. 2012. Bivariate drought frequency analysis using the copula method. Theor. Appl. Climatol. 108: 191-206.
14.Mirabbassi Najafabadi, R., Fakherifard, A., Dinpashoh, Y., and Eslamian, S.S. 2014. Longterm drought monitoring of Urmia using Joint Deficit Index (JDI). Water and Soil Science. 23: 87-103.
(In Persian)
15.Mirakbari, M., and Ganji, A. 2013. A bivariatie analysis of meteorological drought duration and severity (case study: Kermnashah province). Iran Water Res. J. 11: 17-25. (In Persian)
16.Nazemi, A., and Elshorbagy, A.A. 2012. Application of copula modelling to the performance assessment of reconstructed watersheds. Stoch. Environ. Res. Risk Assess. 26: 2. 189-205.
17.Nelsen, R.B. 2006. An Introduction to Copulas, Springer, New York.
18.Omidi, M., Mohammadzadeh, M., and Morid, S. 2010. The probabilistic analysis of drought severity-duration in Tehran province using copula functions. Iran. J. Soil Water Res. 41: 1. 95-101. (In Persian)
19.Rahimi, L., Dehghani, A., Abdolhosseini, M., and Ghorbani, K. 2014. Flood frequency analysis using Archimedean copula functions based on annual maximum series (Case study: Arazkuseh hydrometric station in Golestan province). Iranian Journal of Irrigation and Drainage. 8: 2. 353-365. (In Persian)
20.Sadri, S., and Burn, D.H. 2012. Nonparametric methods for drought severity estimation at ungauged sites. Water Resour. Res. 48: W12505.
21.Shiau, J.T. 2003. Return period of bivariate distributed hydrological events. Stoch. Environ. Res. Risk Assess. 17: 1-2. 42-57.
22.Shiau, J.T. 2006. Fitting drought duration and severity with two-dimensional copulas. Water Resour. Manage. 20: 5. 795-815.
23.Sklar, A. 1959. Fonctions de répartition à n dimensions et leurs marges, Publication of the Institute of Statistics, University of Paris. 8: 229-231.
24.Thilakarathne, M., and Sridhar, V. 2018. Characterization of future drought conditions in the Lower Mekong River Basin. Weather and Climate Extremes. 17: 47-58.
25.Tosunoğlu, F., and Onof, C. 2017. Joint modelling of drought characteristics derived from historical and synthetic rainfalls: application of generalized linear models and copulas. J. Hydrol. Region. Stud. 14: 167-181.
26.Van de Vyver, H., and Van den Bergh, J. 2018. The Gaussian copula model for the joint deficit index for droughts. J. Hydrol. 561: 987-999.
27.Van Loon, A., and Van Lanen, H. 2012. A process- based typology of hydrological dorught. Hydrol. Earth Syst. Sci. 16: 1915-1942.
28.Wong, G., Van Lanen, H., and Torfs, P. 2013. Probabilistic analysis of hydrological drought characteristics using meteorological drought. Hydrol. Sci. J. 58: 2. 253-270.
29.Xu, K., Yang, D., Yang, H., Li, Z., Qin, Y., and Shen, Y. 2015. Spatio-temporal variation of drought in China during 1961-2012: a climatic perspective. J. Hydrol. 526: 253-264.
30.Yang, J., Chang, J., Wang, Y., Li,
Y., Hu, H., Chen, Y., Huang, Q., and Yao, J. 2018. Comprehensive drought characteristics analysis based on a nonlinear multivariate drought index. J. Hydrol. 557: 651-667.
31.Yevjevich, V. 1967. An objective approach to definitions and investigations of continental hydrologic droughts, Hydrologic Paper No. 23, Colorado State University, Fort Collins.
32.Zelenhastic, E., and Salvai, A. 1987. A method of streamflow drought analysis. Water Resour. Res. 23: 1. 156-168.
33.Zhang, L., and Singh, V.P., 2006. Bivariate flood frequency analysis using the copula method. J. Hydrol. Eng. 11: 2. 150-164.
34.Zhang, L., and Singh, V.P. 2007a. Bivariate rainfall frequency distributions using Archimedean copulas. J. Hydrol. 332: 1-2. 93-109.
35.Zhang, L., and Singh, V.P. 2007b. Trivariate flood frequency analysis using the Gumbel-Hougaard copula. J. Hydrol. Eng. 12: 4. 431-439.
36.Zhang, Q., Qi, T., Singh, V. P., Chen, Y. D., and Xiao, M. 2015. Regional frequency analysis of droughts in China: a multivariate perspective. Water Resour. Manage. 29: 6. 1767-1787.