1954. Aging in the masked shrew, Sorex cinereus cinereus Kerr. Jour. Mamm., 35:35-39, February 10.
Rensch, B.
1933. Zoologische systematik und artbildungsproblem. Ver. deutsch. zool. Gesellschaft, 1933:19-83.
Ridgway, R.
1912. Color standards and color nomenclature. Washington, D. C., privately printed, i-iv + 1-44, 53 pls.
Rudd, R. L.
1953. Differentiation in shrews of the tidal marshes of the San Francisco Bay region. Summary of the dissertation for the degree of Doctor of Philosophy, University of California Graduate Division, 4 pages, unnumbered, June.
Simpson, G. G.
1945. The principles of classification and a classification of mammals. Bull. American Mus. Nat. Hist., 85:i-xvi + 1-350, October 5.
Ticehurst, Cl. B.