Manuals
Running and Maintenance Manual
The first book to consult is the Running and Maintenance Instruction Austin provided with every car.
The Sports came with a general 'A40' Models booklet Austin Publication No. 463 and a Sports Supplement Austin Publication No. 782. There are two variants of the supplement, one that covers the GD2 model and one that covers the GD3 model.
Does any reader have a GD2 782/A or 782/B to offer? I would be interested!
A later combined variant is pictured below, Austin PubNo. 881, used ca. 1952.
Service Manual
Austin also published a Service Manual. There is one that covers the A40 Devon Saloon, Austin PubNo. 441, an Austin A40 Sports Advance Supplement, Austin Publication No. 817, and a Service Manual for the Somerset, that covers the Austin A40 Sports as well Austin PubNo. 890.
Parts List
There were three official parts lists:
PubNo. 805 covers the GD2 Sports, an addendum was added for the GD3 model, and a big parts book covering all A40 models PubNo. 1099 which is a great source to cross reference parts.
Additionally there were numerable service manuals published in various counties, here are three examples that I particularly like, from Australia, the Netherlands (a very informative data book) and Germany.