LI BINGJUN. Harmonic Matrix and Harmonic Energy. JOURNAL OF ADVANCES IN MATHEMATICS, [S. l.], v. 6, n. 1, p. 889–895, 2014. DOI: 10.24297/jam.v6i1.3643. Disponível em: https://www.rajpub.com/index.php/jam/article/view/3643. Acesso em: 23 sep. 2025.