1. Erdélyi, A., W. Magnus, F. Oberhettinger and F. G. Tricomi: Higher transcendental functions. I. (Based, in part, on notes left by Harry Bateman, and compiled by the Staff of the Bateman Manuscript Project).-McGraw-Hill Book Company, Inc., New York / Toronto / London, 1953.
2. Frank, E.: A new class of continued fraction expansions for the ratios of hypergeometric functions.-Trans. Amer. Math. Soc. 81, 1956, pp.453–476.
3. New continued fraction expansions for the ratios of hypergeometric functions.-Univ. Lisboa Revista Fac. Ci. (2) A 7, 1959, pp.301–310.
4. Gauß, C. F.: Disquisitiones generales circa seriem infinitam
$$1 + \frac{{\alpha \beta }}{{1.\gamma }}x + \frac{{\alpha (\alpha + 1) \beta (\beta + 1)}}{{1.2.\gamma (\gamma + 1)}} x x + \frac{{\alpha (\alpha + 1) (\alpha + 2) \beta (\beta + 1) (\beta + 2)}}{{1.2.3.\gamma (\gamma + 1) (\gamma + 1) (\gamma + 2)}} x^3 + etc.$$
. Pars prior.-Commentations societatis regiae scientiarum Gottingenesis recentiores. II, Gottingae MDCCCXIII.=Werke. III. [2. Abdruck], pp.123–162. Königliche Gesellschaft der Wissenschaften zu Göttingen, Göttingen, 1876.
5. Perron, O.: Die Lehre von den Kettenbrüchen. I. Elementare Kettenbrüche.-[Dritte Auflage.] B. G. Teubner, Verlagsgesellschaft, Stuttgart, 1954.