King, Ben. "First North American Sighting of Brown Shrike,(Lanius cristatus) and Dusky Warbler (Phylloscopus fuscatus), and Second Record of Red-throated Flycatcher (Ficedula parva)", 1978, Box: 98, Folder: 32. Sauer's Gouldiana Research about John Gould and other papers, MS 304. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/205389 Accessed January 22, 2025.