[1]
E lbert C D,Pau l J,R obert N K,et a l.R idge p lan t system s:equ ipm en t,G 88 876 A[K].Cooperative Ex tens ion,Institu te of A gricu lture and N atura l R esources,U n ivers ity of N ebraska,L inco ln,1996
[1]
E lbert C D,Pau l J,R obert N K,et a l.R idge p lan t system s:equ ipm en t,G 88 876 A[K].Cooperative Ex tens ion,Institu te of A gricu lture and N atura l R esources,U n ivers ity of N ebraska,L inco ln,1996