Annotated bibliography of Pennsylvania geology--supplement to 1959 /

by Cramer, Howard Ross, 1925-
Harrisburg : Dept. of Internal Affairs, Bureau of Topographic and Geologic Survey; [for sale by the Division of Documents, Bureau of Publications], 1965

Annotated bibliography of Pennsylvania geology to 1949.

by Cramer, Howard Ross, 1925-
[Harrisburg] Dept. of Internal Affairs, Topographic and Geologic Survey, 1961

Annotated bibliography of Pennsylvania geology -- supplement to 1969.

by Cramer, Howard Ross, 1925-
Harrisburg, [Commonwealth of Pennsylvania, Bureau of Topographic and Geologic Survey] 1972