Sarma, P. A. “Families of Third, Fourth and Fifth Order Extended Nystrom Methods for \(y’’’=f( x,y)\)”. Anal. Numér. Théor. Approx. 20, no. 1 (August 1, 1991): 83–95. Accessed November 23, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1991-vol20-nos1-2-art12.