BHATIA, A. K. Variational Principles and Their Applications. Journal of Atomic, Molecular, Condensed Matter and Nano Physics, [S. l.], v. 12, n. 1, p. 9–26, 2025. DOI: 10.26713/jamcnp.v12i1.3018. Disponível em: https://www.rgnpublications.com/journals/index.php/jamcnp/article/view/3018. Acesso em: 5 dec. 2025.