Higuchi et. al, "The Physics of Tablet Compression XI, Determination of Porosity of Tablet Granulations,", 1956, Box: 11, Folder: 49. Personal papers of Takeru Higuchi, PP 359. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/124683 Accessed March 11, 2025.