Reference Material

Whats everyones favourite reference material on aircraft besides of course this wonderful magazine and your most knowledgable selves?
Mine is my 120 issues of Warplane magazine that was printed from 1985-1988(a magnificent piece of reference material, if slightly outdated on some issues now), Airforces of the World by Christopher Chant and The Complete Book of Fighters by William Green and Gordon Swanborough (HUGE!). Apart from Jane’s assorted volumes, what else should be added to a military aircraft reference library?