@article{1183530830,
author = {Chen, Kuo-Tsai},
title = {An algebraic dualization of fundamental groups},
journal = {Bull. Amer. Math. Soc.},
volume = {75},
number = {5},
year = {1969},
pages = { 1020-1024},
language = {en},
url = {http://dml.mathdoc.fr/item/1183530830}
}
Chen, Kuo-Tsai. An algebraic dualization of fundamental groups. Bull. Amer. Math. Soc., Tome 75 (1969) no. 5, pp. 1020-1024. http://gdmltest.u-ga.fr/item/1183530830/