* Linguistics 

Encyclopedia of language and linguistics. R.E. Asher, Ed. New York: Pergamon Press, 1994.
10 volumes. Reference: P29.E48 1994

Encyclopedia of language and linguistics. Second edition. Keith Brown, Ed. Boston: Elsevier, 2006.
14 volumes. Available online through Science Direct.

The handbook of linguistics. Mark Aronoff and Janie Rees-Miller, Eds. Malden: Blackwell, 2001.
Reference and Leavey: P121.H324 2001

International encyclopedia of linguistics. Second edition. William J. Frawley, Ed. New York: Oxford University Press, 2003.
4 volumes. Reference and Philosophy: P29.I58 2003 Available also in Oxford Digital Reference Shelf.

Linguistics: a guide to the reference literature. Anna L. DeMiller, Comp. Englewood: Libraries Unlimited, 2000.
Reference: Z7001.D45 2000