@article{bwmeta1.element.bwnjournal-article-cmv9i1p1bwm,
author = {Roman Sikorski},
title = {Algebra of formalized languages},
journal = {Colloquium Mathematicae},
volume = {9},
year = {1962},
pages = {1-31},
zbl = {0104.24103},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-cmv9i1p1bwm}
}
Sikorski, Roman. Algebra of formalized languages. Colloquium Mathematicae, Tome 9 (1962) pp. 1-31. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-cmv9i1p1bwm/