Proto Indo European

American Heritage Dictionary - Appendix I: Indo-European Roots, Calvert Wakins, 5th Edition

The American Heritage Dictionary Of Indo-European Roots, Calvert Watkins, Third Edition

Early Indo-European, Linguistics Research Center, Univeristy of Texas - Austin

Indo-European Language and Culture: An Introduction, Benjamin W. Fortson IV, Blackwell Textbooks in Linguistics

Indo-European Linguistics: An Introduction, James Clackson, Cambridge Textbooks in Linguistics

The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World, J. P. Mallory, Oxford Linguistics