compiled under the supervision of Hazel Hunt Voth and John C. Benton at the Western Museum Laboratories of the National Park Service, with assistance provided by the Work Projects Administration and Civilian Conservation Corps
compiled at the Western Museum Laboratories of the National Park Service with assistance provided by the Work Projects Administration and the Civilian Conservation Corps
compiled under the supervision of Hazel Hunt Voth and Dr. Carl P. Russell, at the Western Museum Laboratories of the National Park Service ; with the assistance provided by the Work Projects Administration and Civilian Conservation Corps