Primary
Library of Congress, Prints and Photographs Division, FSA-OWI Collection, Reproduction Nos. LC-USF34-033871-D and LC-USF34-033874-D, July 1939, Russell Lee, photographer.
20778.AG.AL.1.1. Edd Roberts Collection. - Photographs. - Box 1. AGRICULTURE - LIVESTOCK - SWINE - "AARON GRITZMAKER, LAHOMA, GARFIELD CO. WITH GRAND CHAMPION BARROW OF THE AMERICAN ROYAL, KANSAS CITY, MO. OKLAHOMA'S PIG CLUB ENROLLMENT IN 1938 WAS 5, 735. NUMBER OF MEMBERS COMPLETING - 4,585. NUMBER IF ANIMALS IN PROJECTS - 11, 472." PHOTO BY GUY E. SMITH, KANSAS CITY, MO., 1938
Secondary
“River Polution.” Blogspot, 3.bp.blogspot.com/-__wRs-Qa7eo/Ud2i0h_Vk4I/AAAAAAAAMXE/kyNoyeQdglo/s1600/P1010896.JPG .
“Learnnc.” Learnnc, www.learnnc.org/lp/media/uploads/2010/01/855680188_aaadab38cf_b.jpg .
“Pollution.” Civil Works, civileats.com/wp-content/uploads/2016/03/16005857314_ea882b615d_k.jpg .