Site indexes for Engelmann spruce - Alexander, Robert R.; Rocky Mountain Forest; Range Experiment Station (Fort Collins, Colo.) (Fort Collins, Colo, Rocky Mountain Forest and Range Experiment Station, Forest Service, U.S. Dept. of Agriculture, 1967)
https://www.biodiversitylibrary.org/bibliography/98783
Keywords: Colorado|Engelmann spruce|Site index (Forestry)|Wyoming