1. Euler, L. 1741.Inventio Summae cuiusque seriei ex dato termino generali, Vol. 8, 9–22. St Petersburg: Commentarii Academiae Scientiarum Petropolitanae.
2. Table des valeurs des sommes
$S_k = \sum\limits_1^\infty {n^{ - k} } $
3. Analytic Eisenstein series, theta-functions, and series relations in the spirit of Ramanujan.
4. Gourdon, X. and Sebah, P. 2006. “Numbers, constants and computation”. Available online at:http://numbers.computation.free.fr/Constants/constants.html