Vibrational spectra and theoretical studies of tautomerism and hydrogen bonding in the violuric acid and 6-amino-5-nitrosouracil system - Bonacin, Juliano Alves; Formiga, André Luiz Barboza; Melo, Vitor Hugo Soares de; Toma, Henrique Eisi (Vibrational Spectroscopy, 2007)