Nielsen, Melanie; Hoogvorst, Anneke; Konradsen, Flemming; Mudasser, Muhammad; Van Der Hoek, Wim(International Water Management Institute, Colombo, Sri Lanka, 2001)
Gebremedhin, Berhanu; Pender, John; Girmay, Tesfaye(Environment and Production Technology Division, International Food Policy Research Institute, 2000)