@article{1183540396,
author = {Kechris, A. S. and Martin, D. A.},
title = {On the theory of $\Pi \_3^1$ sets of reals},
journal = {Bull. Amer. Math. Soc.},
volume = {84},
number = {6},
year = {1978},
pages = { 149-151},
language = {en},
url = {http://dml.mathdoc.fr/item/1183540396}
}
Kechris, A. S.; Martin, D. A. On the theory of $\Pi _3^1$ sets of reals. Bull. Amer. Math. Soc., Tome 84 (1978) no. 6, pp. 149-151. http://gdmltest.u-ga.fr/item/1183540396/