Godswill Makombe, Regassa E Namara, Seleshi Bekele Awulachew, Fitsum Hagos, Mekonnen Ayana, and Matshidiso Kanjere, “An analysis of the productivity and technical efficiency of smallholder irrigation in Ethiopia”, WSA, vol. 43, no. 1 January, Jan. 2017, doi: 10.4314/wsa.v43i1.08.