Popoviciu, Elena. “Sur Certaines Allures Remarquables: On Some Remarkable Allures”. Rev. Anal. Numér. Théor. Approx., vol. 26, no. 1, Aug. 1997, pp. 197-02, https://www.ictp.acad.ro/jnaat/journal/article/view/1997-vol26-nos1-2-art26.