It is a shame that such a resource doesn't exist, but there is the Kitchen Sink reprint of the Yellow Kid tear sheets, there are a few book chapters, a couple of journal articles, and my web site. And because I don' keep up with such things as carefully as I used to, there may well be additional sources I am not familiar with. However, given the age of his material and the wide variety of publications he created in addition to Sunday newspaper cartoons, I doubt that such a resource could be compiled. Still, I don't mind as it is very exciting to find a Yellow Kid item that I didn't know existed.