@book{30343,
	author = {Siva Kumar, M. V. K.},
	title = {Drought spells and drought frequencies in west Africa =},
	publisher = {International Crops Research Institute for the Semi-arid Tropics,},
	year = {1991.},
	address = {Patancheru, Andhra Pradesh, India :},
	note = {English and French.}
}