Daugherty, W.; Dunn, K.; Hackney, B.; Hoffman, E. & Skidmore, E. 9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY, report, January 6, 2011; (https://digital.library.unt.edu/ark:/67531/metadc837187/m1/1/: accessed April 26, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .