Balázs, M. “On a Method of Third Order in Fréchet Spaces”. Anal. Numér. Théor. Approx. 12, no. 1 (February 1, 1983): 5–10. Accessed April 14, 2025. https://ictp.acad.ro/jnaat/journal/article/view/1983-vol12-no1-art1.