For the basic discovery of resonance see "Kekule"

http://en.wikipedia.org/wiki/Friedri...von_Stradonitz

For advanced work see "Hammett".

http://en.wikipedia.org/wiki/Hammett_equation

For the answer as to whether 1,3-Budadiene-1,4-diamine is a developer consider the exceptions to this rule and consider the extensions by Umberger.

I would not work with it either and I doubt if anyone would in a small darkroom, and therefore there will never be any real way to prove whether it is or is not.

PE