Found in articles
the Online Etymology Dictionary. Robert S. P. Beekes, Etymological Dictionary of Greek, Brill, 2009, pp. 269–270 (s.v. "γῆ"). „Paleolexicon”. Приступљено
nationalgeographic.com. Архивирано из оригинала 20. 10. 2014. г. Robert S. P. Beekes|R. S. P. Beekes, Etymological Dictionary of Greek, Brill, (2009). стр. 1261)
Liddell, Robert Scott, A Greek–English Lexicon, on Perseus Digital Library R. S. P. Beekes, Etymological Dictionary of Greek, Brill, 2009, p. 907. „Definition
translated by Mary A. Grant, Lawrence: University of Kansas Press, 1960. Beekes, Robert S. P. (2009). Etymological Dictionary of Greek. Brill. ISBN 978-90-04-32186-1
Religions. Wilfrid Laurier Univ. Press. ISBN 978-0-88920-421-8. Robert S.P. Beekes (2011). Comparative Indo-European Linguistics: An introduction (2nd