Coutinho, C.M., Bassini, A.S., Gutiérrez, L.G., Butugan, O., Kowalski, L.P., Brentani, M.M. and Nagai, M.A. 1999. Genetic alterations in Ki-ras and Ha-ras genes in Juvenile Nasopharyngeal Angiofibromas and head and neck cancer. São Paulo Medical Journal. 117, 3 (May 1999), 113–120.