"Essays on Cellular Automata" by Arthur Burks is a good starting point. Then there's the proceedings of the conference, "International Conference on Cellular Automata for Research and Industry".

Start by going to a good library and checking out the proceedings of the Artificial Life (ALIFE) conference. Read the papers and start following the references.

For something less academic and more "look at cool stuff" there's also https://www.reddit.com/r/cellular_automata/

In addition to the more directly related stuff others have mentioned it's also relevant and interesting to dive into Complex Adaptive Systems literature if you have the inclination, for the classic order-from-chaos essays and discussions of emergent properties and so on.