I use the definitive source - Bradford Northern - The History 1863-1989 by Nigel Williams. Nigel was the "guru" of the stats and the official club statistician for years. Unfortunately nobody at the club seems to know where he is now. We have his book which has stats on everything for that period.
I'm trying to get that down electronically and am working on adding stats the period where he left off until now and ongoing. It'd be good to get stuff on wikipedia updated for our players. I can provide the stats if you can be bothered updating them?