A pale mutation in the ground squirrel: An Albinoid Color-phase in Citellus elegans Resembling the Recessive Cream Mutation in the Rat. Frank H. Clark and William L. Jellison, J Hered (1937) 28 (7), pages 259-260, doi10.1093/oxfordjournals.jhered.a104375
Life-history studies of the Wyoming ground squirrel (Citellus elegans elegans) in Colorado. William L. Burnett, Bulletin of the Colorado Agricultural Experiment Station, 1931 (URL)