Abramowitz, M. & Stegun, A. (1965). Handbook of Mathematical Formulas, Graphs, and Mathematical Tables. Dover Publications, Inc, New York, USA.
Beheshtirad, M. (2015). Investigation spatial variation of drought using geostatistics methods and Z index in Kerman province. J Irrigation and Water Engineering, 5(20), 118-130.
Benjamin, L. H. & Saunders, A. (2002). A drought climatology for Europe Int. J. climatol. 22, 1571-1592.
Farajzadeh, M. (1997). Drought study methods. Forest and Range, 32, 22-28 (In Persian).
Ghahremani, E. (2015). Analysis of meteorological and hydrological drought in zohreh river basin. M.S. Thesis, Water Science and Engineering, Islamic Azad University, Marvdasht branch, Marvdasht, Iran (In Persian).
Hayes, M. J., Svoboda, M. D., Wilhite, D. A. & Vanyarkho, O. V. (1999). Monitoring the 1996 drought using the Standardized Precipitation Index. Bulletin of the American Meteorological Society, 80, 429–438.
Henriques, A. G. & Santos, M. J. (1999). Regional drought distribution Model. Phys, Chem, Earth, 24(1-2), 19-22.
Janbozorgi, M., Hanifepour, M. & Khosravi, H. (2021). Temporal changes in meteorological-hydrological drought (case study: Guilan province). Water and Soil Management and Modeling, 1(2), 1-14 (In Persian).
Keshtkar, A.R., Moazami, N. & Afzali, A. (2021). Assessment of spatial interpolation techniques for drought severity analysis in Iran’s Salt Lake Basin. Desert, 26(1), 85-97 (In Persian).
Khan, S., Gabriel, H.F. & Rana, T. (2008). Standard precipitation index to track drought and assess impact of rainfall on water tables in irrigation areas, Irrig Drainage Syst, 159–17.
Matalas, N. C. (1991). Drought description. Stochastic Hydrology and Hydraulics, 5, 255-260.
Mckee, T.B., Doesken, N.J. & Kleist, J. (1993). The Relationship of drought Frequency and Duration to Time Scales, 8th Conference on Applied Climatology, 179-184.
Mckee, B. T., Nolan, J. & Doesken, Kleist, J. (1995). Drought monitoring with multiple timescales, 9th Conference on Applied Climatology, Boston, Massachusett.
Mehry, S., Haji, K., Alizadeh, V. & Mostafazadeh, R. (2017). Assessment of spatial variations of meteorological drought periods severity in Kurdistan Province at different time scales. Geographical Data, 26(102), 151-162 (In Persian).
Mesbahzadeh, T. & Soleimani Sardoo, F. (2018). Temporal Trend Study of Hydrological and Meteorological Drought in Karkheh Watershed. Iran-Watershed Management Science and Engineering, 12(40), 105-114 (In Persian).
Mostafazadeh, R., Shahabi, M. & Zabihi, M. (2015). Analysis of meteorological drought using Triple Diagram Model in the Kurdistan Province, Iran. Geographical Planning of Space, 5(17), 129-140 (In Persian).
Mishra, A.K. & Desai, V.R. (2005). Drought Forecasting Using Stochastic Models, Stochastic Environmental Research and Risk Assessment (SERRA), 19(5), 326-339.
Moradi, H. R., Rajabi, M. & Faragzadeh, M. (2011). Investigation of meteorological drought characteristics in Fars province, Iran, Catena 84, 35–4.
Razmkhah, H., Akhond Ali, A.M. & Saghafian, B. (2009). Evaluation of yearly precipitation regional variation using Kriging geostatistical technique, case study: Fars Province, The Second National Seminar on Drought Effects/Management, Esfahan (In Persian).
Razmkhah, H. & Safi, Z. (2012). Analysis if Bakhtegan basin Hydrological drought. 4th Iran Water Resources Management Conference, Tehran, Iran (In Persian).
Razmkhah, H. & Saghafian, B. (2011). Assessing spatial variation of SPI 3-months, using geostatistic technique, case study: Fars Province. 4th Iran Water Resources Management Conference, Tehran, Iran (In Persian).
Razmkhah, H. (2016). Preparing stream flow drought severity-duration-frequency curves using threshold level method, Arabian J. of Geosciences, 9, 513.
Razmkhah, H. (2017). Comparing threshold level methods in development of stream flow drought severity-duration-frequency curves, Water Resources Management, 31, 4045–406.
Rostami, E. (2013). Monitoring and prediction of hydrological drought in Kohgilouyeh and BoyerAhmad province, using meteorological drought indexes and Artificial Neural Networks. M.S. Thesis, Water science and engineering, Islamic Azad University, Marvdasht branch, Marvdasht, Iran (In Persian).
Subedi, M.R., Xi, W., Edgar, Ch. B., Rideout-Hanzak, S. & Hedquist, B.C. (2019). Assessment of geostatistical methods for spatiotemporal analysis of drought patterns in East Texas, USA. Spatial Information Research: 27, 11–21.
Zamani, R., Akhondali, A.M., Solaimani, K., Ansari, F. & Allahbakhshian, P. (2012). Application of geostatistics in zone classification of drought severities (case study: Fars province). J Watershed Management Research, 3(6), pp. 15-29 (In Persian).
Zandifar, S., Fijani, E., Naeimi, M. & Khosroshahi, M. (2020). Spatiotemporal variations of groundwater drought indices, Case study: Zohreh- Jarrahi watershed. Hydrogeology, 4(2), 180-130 (In Persian).
Zarea Abyaneh, H., Mahboubi, A.A. & Neyshabouri, M.R. (2004). Evaluation of drought situation and its process in Hamadan region on the basis of drought statistical indexes. Pajouhesh-va-Sazandegi, 17(3), 2-17 (In Persian).
