When looking for reliable sources of information about gardening, one place to start is at the land grant college in your state. Here in Georgia, that's UGA. It offers a search function on its publications website that can be used to find all sorts of great information.
Publications span a wide range of topics and include a booklet-length text on Growing Vegetables Organically. We handed these out at yesterday's talk on raised bed gardening, but we didn't have enough for everyone. (To get an electronic copy from the linked page, choose which version you want, either html or pdf, and it will appear!) UGA offers publications on individual veggies and fruits, on composting and many other relevant topics.
The good news is that most County Extension offices will send, through the mail, paper copies of their publications if a citizen in the county requests the information. Later in the week, when I get to the Cobb County Extension office, I will be putting together a couple of envelopes full of information for people who came to the talk but missed out on the handouts.
Other sources of information include experienced gardeners, some of whom will have published information in magazines and newspapers. Yesterday, someone asked about growing vegetables in the shade. Amazingly enough, when I opened my email this morning, the most recent note from Mother Earth News included an article on growing veggies in shade.
The article, Best Vegetables to Grow in the Shade, includes a link to a handy table of veggies and their minimum sunlight requirements along with the general discussion on maximizing availability of sunlight to a shaded garden.