SINGBAL, B. V. Algebraic Basis of Morse’s Variational Theory. The Journal of the Indian Mathematical Society, [S. l.], v. 18, n. 1, p. 131–165, 1954. DOI: 10.18311/jims/1954/17023. Disponível em: https://www.informaticsjournals.com/index.php/jims/article/view/17023. Acesso em: 4 may. 2024.