Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2019. The eBird/Clements Checklist of Birds of the World: v2019. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/ March 5, 2021
Pendergast, B. A.; Boag, D. A. (1971). "Nutritional Aspects of the Diet of Spruce Grouse in Central Alberta". The Condor. 73 (4): 437–443. doi:10.2307/1366665. JSTOR1366665.
Pendergast, B. A.; Boag, D. A. (1971). "Nutritional Aspects of the Diet of Spruce Grouse in Central Alberta". The Condor. 73 (4): 437–443. doi:10.2307/1366665. JSTOR1366665.