1. H. Poincaré: Acta Math. VIII, 295 (1886)
2. E.T. Whittaker, G.N. Watson: Modern Analysis, 4th ed. (Cambridge University Press, London 1952)
3. G.G. Stokes: Trans. Cambridge Philos. Soc. 9, 165 (1856);
4. G.G. Stokes: Trans. Cambridge Philos. Soc. 10, 105 (1857);
5. G.G. Stokes: Trans. Cambridge Philos. Soc. 11, 412 (1871)