"Twins, Part 1: The Conception, Development, and Delivery of Twins" by Garfield, Eugene, 1984

"Twins, Part 1: The Conception, Development, and Delivery of Twins" by Garfield, Eugene, 1984, Box: 3, Folder: 54. Personal papers of John "Jack" A. Weir, PP 404. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/261314 Accessed December 25, 2025.