This is a classic text in the area and has aged quite gracefully. It is a good general reference for this course.
This was the previous textbook I used for CS 5104. It is a little gentler than Hopcroft and Ullman and is also a good general reference. The book has an excellent notation for building composite Turing machines.
This is the text I use for CS 4114, the undergraduate course in formal languages and automata. It is a more elementary text than Sipser, Hopcroft and Ullman, or Lewis and Papadimitriou.
This is an interesting collection of early work on automata. See especially the paper on the Firing Squad Synchronization Problem.
This is a collection of chapters on strings as combinatorial objects.
A small book on some interesting problems related to strings and languages.
Please report any problems found in these pages to: CS 5104 EI Account (cs5104@ei.cs.vt.edu)