[1] Petca A, Borislavschi A, Zvanca ME, Petca RC, Sandru F, Dumitrascu MC. Non-sexual HPV transmission and role of vaccination for a better future (Review). Exp Ther Med. 2020;20(6):186. doi:10.3892/etm.2020.9316
[2] Heymann MD (2015). Control of Communicable Diseases Manual (20th ed.). Washington D.C.: Apha Press. pp. 299–300. ISBN 978-0-87553-018-5.