%0 Journal Article
%A Lyndon, R. C.
%A Ullman, J. L.
%T Groups Generated by two Parabolic Linear Fractional Transformations
%J Canadian journal of mathematics
%D 1969
%P 1388-1403
%V 21
%N 1
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1969-153-1/
%R 10.4153/CJM-1969-153-1
%F 10_4153_CJM_1969_153_1