1. A comparative study of critical drought simulation;Askew;Water Resour. Res.,1971
2. Drought severity and water supply dependability;Beard;J. Irrig. Drain. Div., Amer. Soc. Civil Eng.,1972
3. On the definition of droughts;Dracup;Water Resour. Res.,1980
4. Huff , F. A. S. A. Changnon Jr. Relation between precipitation, drought and low streamflow, Surface Water, Publ 63 167 180 Int. Ass. Sci. Hydrol. Gentbrugge, Belgium 1964