R. L.  Squires, ?New stratigraphic and geographic occurences of Isognomon (Mollusca: Bivalvia) from the Eocene of California and Oregon?, Transactions of the San Diego Society of Natural History, vol. 21, pp. 275-282, 1989.

R. L.  Squires, ?New stratigraphic and geographic occurences if Isognomon (Mollusca: Bivalvia) from the Eocene of California and Oregon?, Transactions of the San Diego Society of Natural History, vol. 21, pp. 275-282, 1989.