==Bibliography==*Old Norse Literature and Mythology (1969)*Language in Tanzania (1980)*Language, Society and Paleoculture (1982)*The Indo-Europeans in the Fourth and Third Millennia B.C.
* Old Norse Literature and Mythology (1969)* Language in Tanzania (1980)* Language, Society and Paleoculture (1982)* The Indo-Europeans in the Fourth and Third Millennia B.C.