9Watts K C, Bilanski W K. Stress relaxation of alfalfa under constant displacement [ J]. Transactions of the ASAE, 1991, 34(6) : 2491 -2498.
10Nazari Galedara M, Jafaria A, Mohtasebia S S, et al. Effects of moisture content and level in the crop on the engineering properties of alfalfa stems [ J]. Biosystems Engineering, 2008, 101 (2) : 199 - 208.