@article{GDZPPN002308509, title = {A Direct Proof of a Theorem of Roth.}, journal = {Mathematische Annalen}, volume = {201}, year = {1973}, pages = {1-8}, zbl = {0244.10040}, url = {http://dml.mathdoc.fr/item/GDZPPN002308509} }
Choi, S.L.G. A Direct Proof of a Theorem of Roth.. Mathematische Annalen, Tome 201 (1973) pp. 1-8. http://gdmltest.u-ga.fr/item/GDZPPN002308509/