PORKURIAN, O.; TIMOSHYN, A.; DAVYDENKO, V. DISCRETE MATHEMATICS TEXTBOOK. Kharkiv: TECHNOLOGY CENTER PC, 2016. DOI: 10.15587/978-617-7319-03-9. Disponível em: https://doi.uran.ua/index.php/pctc/catalog/book/978-617-7319-03-9. Acesso em: 21 apr. 2025.