V.GOVINDAN; S.DHIVYA. QUAD DIFFERENCE LABELLING ON SOME GRAPHS. International Journal of Technical Innovation in Modern Engineering & Science, [S. l.], v. 5, n. 4, p. 694–697, 2019. Disponível em: https://ijtimes.com/index.php/ijtimes/article/view/2784. Acesso em: 8 jan. 2025.