Păvăloiu, Ion. “ On Computational Complexity in Solving Equations by Steffensen-Type Methods”. Rev. Anal. Numér. Théor. Approx., vol. 24, no. 1, Aug. 1995, pp. 215-9, https://ictp.acad.ro/jnaat/journal/article/view/1995-vol24-nos1-2-art23.