Humidity and action regulation

[Glenn A. Vallespir]

I am interested in learning about humidity and its effects on the action 
parts and regulation. Can anyone suggest a bibliography of articles on the 
subject. I am particularly interested in the causes of the changes I am 
seeing these days. 20% humidity is common in the homes I visit. I am 
selling lots of Dampp Chasers. Extreme changes in lost motion and 
disappearing key dip are resulting in a lot of double striking notes. I'd 
like to gain a clear understanding of the geometry changes that are 
occurring. I am also looking to gain more information on sunlight and its 
effects on the piano. I would like very much to come up with a couple of 
articles that I can duplicate or purchase, similar to the PTG tech 
bulletins. I am constantly trying to educate my customers, but I have found 
that having something in writing tends to validate my teaching efforts as 
well as allowing me to get on with the job at hand.

Thank you,
Glenn
Key Note Piano Service