M. Zamanian, , , S. A. Siadat, , , Gh. Fathi, , , R. Choukan, , , A. A. Jafari, , and A. Bakhshandeh, . "Assessment of Required Growing Degree Days for Phenological Stages of Four Clover Species in Different Planting Dates", Seed and Plant Production Journal, 29, 2, 2013, 149-167. doi: 10.22092/sppj.2017.110507