Nega Tolla, Pravee Vijchulata, Pornsri Chairatanayuth and Suwapong Swsdiphanich 2006. Comparative Performances of Holstein-Friesian Cows under Smallholder and Large Scale Farmers’ Management in Central Rift Valley, Ethiopia. Agriculture and Natural Resources. 40, 1 (Feb. 2006), 58–68.