Shock, C.C.; Feibert, E.B.G.; Rivera, A; Saunders L.D.; Shaw, N.; Kilkenny, F. 2015a. Irrigation requirements for seed production of five native Penstemon species in a semi-arid environment. In: Shock, C.C., ed. Malheur Experiment Station Annual Report 2014, Ext/CrS 152. Corvallis, OR: Oregon State University: 217-230.

Shock, C.C.; Feibert, E.B.G.; Rivera, A; Saunders L.D.; Shaw, N.; Kilkenny, F. 2015a. Irrigation requirements for seed production of five native Penstemon species in a semi-arid environment. In: Shock, C.C., ed. Malheur Experiment Station Annual Report 2014, Ext/CrS 152. Corvallis, OR: Oregon State University: 217-230.