1. Richard Askey and Mourad Ismail, A combinatorial sum, MRC Technical Summary Report #1557, July 1975, unpublished.
2. W. N. Bailey, Generalized hypergeometric series, Cambridge Univ. Press, London, 1935.
3. Ramanujan’s Notebooks
4. G. H. Hardy, A chapter from Ramanujan’s note-book, Proc. Cambridge Philos. Soc. 21 (1923), 492-503.