1. Schumann JL, O’Connor DM, Covell JL, Greening SE. Pap smear collection devices: technical, clinical, diagnostic, and legal considerations associated with their use. Diagn Cytopathol. 1992;8(5):492–503.
2. Martin-Hirsch P, Jarvis G, Kitchener H, Lilford R. Collection devices for obtaining cervical cytology samples. Cochrane Database Syst Rev. 2000;(2):CD001036.
3. NCCLS. Nongynecologic cytologic specimens: collection and cytopreparatory techniques; approved guideline. NCCLS document GP 23-A[ISBN 1-56238-380-9]. Wayne: NCCLS; 1999.
4. Nongynecologic cytology practice guideline. Acta Cytol. 2004;48(4):521–46.
5. Jain D, Mathur SR, Iyer VK. Cell blocks in cytopathology: a review of preparative methods, utility in diagnosis and role in ancillary studies. Cytopathology. 2014;25(6):356–71.