The national parks portfolio,
by Robert Sterling Yard.

APA Citation

United States. National park service. [from old catalog]., Yard, R. Sterling. (1917). The national parks portfolio. [2d ed.] Washington, D.C.: Govt. print. off..

MLA Citation

United States. National park service. [from old catalog], and Robert Sterling Yard. The National Parks Portfolio. [2d ed.] Washington, D.C.: Govt. print. off., 1917.