Nega Tolla, Pravee Vijchulata, Pornsri Chairatanayuth, and Suwapong Swsdiphanich, “Comparative Performances of Holstein-Friesian Cows under Smallholder and Large Scale Farmers’ Management in Central Rift Valley, Ethiopia”, Agr. Nat. Resour., vol. 40, no. 1, pp. 58–68, Feb. 2006.