Interested in those 1930s guides to the states I am drawing this blog from? Most libraries will have a copy for that state, and bigger libraries may have those for other states as well. If you're curious about what's out there in libraries, check your local library website. A site that works for the whole US is WorldCat.org, which draws on library catalogs from all over to tell what's around.
You can buy the guidebooks too, they are often available at used book dealers for modest prices. A good online site is abebooks.com - in the author line put writers project, and in title put "state name."