A note on the accuracy of Ramanujan's approximative formula for the perimeter of an ellipse. Villarino, Mark B. — 2006 JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]
Ramanujan's harmonic number expansion into negative powers of a triangular number. Villarino, Mark B. — 2008 JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]