^Campbell, Lyle; Mixco, Mauricio, Korean, A language isolate, A Glossary of Historical Linguistics, University of Utah Press: 7, 90–91, 2007, most specialists... no longer believe that the... Altaic groups... are related […] Korean is often said to belong with the Altaic hypothesis, often also with Japanese, though this is not widely supported.
^Dalby, David, The Register of the World's Languages and Speech Communities, Linguasphere Press, 1999–2000.
^Kim, Nam-Kil, Korean, International Encyclopedia of Linguistics 2: 282–86, 1992, scholars have tried to establish genetic relationships between Korean and other languages and major language families, but with little success.
^Róna-Tas, András, The Reconstruction of Proto-Turkic and the Genetic Question, The Turkic Languages, Routledge: 67–80, 1998, [Ramstedt's comparisons of Korean and Altaic] have been heavily criticised in more recent studies, though the idea of a genetic relationship has not been totally abandoned.
^Schönig, Claus, Turko-Mongolic Relations, The Mongolic Languages, Routledge: 403–19, 2003, the 'Altaic' languages do not seem to share a common basic vocabulary of the type normally present in cases of genetic relationship.