Ripeanu, Dumitru. “Intervalles d’interpolation Pour Des Classes d’équations différentielles Du Second Ordre: Interpolations Intervals for Some Classes of Second Order Differential Equations”. Anal. Numér. Théor. Approx. 14, no. 1 (February 1, 1985): 59–81. Accessed November 22, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1985-vol14-no1-art4.