in descending order of usage:

1. The main course textbook:
   H. Abelson and G.J. Sussman: Structure and Interpretation of Computer Programs. The MIT Press. 2nd edition. 1996.
   http://mitpress.mit.edu/sicp/full-text/book/book.html

2. Textbook for type related sections and for MLchapter (6).
   L. Paulsen: ML for the Working Programmer. 2nd ed. 1996. Cambridge university press.

3. Textbook for the logic programming chapter (7).
   Leon Sterling & Ehud Shapiro, The Art of Prolog, MIT Press, 1986.

4. Textbook for the contracts related subjects:
   M.Felleisen, R.B.Findler, M.Flatt and S. Krishnamurthi: How to Design Programs. 2003. The MIT Press.
   http://www.htdp.org/2003-09-26/Book/

5. Friedman:
   D.P. Friedman, M. Wand, C.T. Haynes: Essentials of Programming Languages. 2nd edition, MIT Press, 2001.

6. Krishnamurthi:
   S. Krishnamurthi: Programming Languages: Application and Interpretation. Version 26.4.2007.
   http://www.cs.brown.edu/~sk/Publications/Books/ProgLangs/2007-04-26/

7. H.E. Bal and D. Grune: Programming Language Essentials. 1994. Addison-wesley.