Britton, Joseph; Hagan, J.; Graham & Champagne, L. Utterbackia imbecillis, Specimen #1314, specimen, June 1, 1977; (https://digital.library.unt.edu/ark:/67531/metadc35126/m1/1/: accessed November 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .