1. Adams 1 9 2 2 " Smithsonian M athematical Formulae and Tables o f Elliptic Functions." Smithsonian Institution U .S.A . .
2. Basset 1884 Q uart.
3. Bromwich 1 9 0 8 " Theory o f Infinite Series."
4. J .M a th . 20 234. M acmillan and Co. Ltd.
5. Davis 1 9 3 3 193 5 " Tables o f the Higher M athematical Functions" 2 vols. Vol. 1 contains the digam ma function vol. 2 the trigamma function. Principia Press Inc. U .S.A . See also British Association for the Advancem ent of Science 1931 " M athematical T ables" 1 . British Association Burlington House.