Room for improvement: initial experience with anal cytology: observations from the College of American Pathologists interlaboratory comparison program in nongynecologic cytology - Darragh, T M; Winkler, B; Souers, R J; Laucirica, R; Zhao, C; Moriarty, A T (Arch Pathol Lab Med, 2013)
; College of American Pathologists Cytopathology Committee.