Hi, Charlene: I don't find the Timmer reference in the sources I've been using. As I recall, the Timmer reference to adolescents was already in the text when I signed on to Wikipedia. I've worked around the statement, but I don't know the source. I checked the Timmer article on Wikipedia and didn't see it there. Sorry, I can't be of more help. Mike Klaassen
Charlene, did you ever find the source for the Timmer comment? Mike Klaassen