SAMODUROV, Alexander; CVEJIĆ, Stana. METHOD OF VARIATION OF PARAMETERS IS NOT EXHAUSTED. Matematichki Bilten, [S. l.], v. 16, n. 1, p. 81–83, 1992. Disponível em: https://bilten.smm.org.mk/index.php/bilten/article/view/1494. Acesso em: 14 aug. 2026.