@article{1077492641,
author = {Duffin, R. J. and Schaeffer, A. C.},
title = {Khintchine's problem in metric Diophantine approximation},
journal = {Duke Math. J.},
volume = {8},
number = {1},
year = {1941},
pages = { 243-255},
language = {en},
url = {http://dml.mathdoc.fr/item/1077492641}
}
Duffin, R. J.; Schaeffer, A. C. Khintchine’s problem in metric Diophantine approximation. Duke Math. J., Tome 8 (1941) no. 1, pp. 243-255. http://gdmltest.u-ga.fr/item/1077492641/