Voir la notice de l'article provenant de la source Czech Digital Mathematics Library
@article{KYB_1967__3_4_a0, author = {Kr\'al, Jaroslav}, title = {Set-theoretical operations on $k$-multiple languages}, journal = {Kybernetika}, pages = {--320}, publisher = {mathdoc}, volume = {03}, number = {4}, year = {1967}, zbl = {0155.01604}, language = {en}, url = {http://geodesic.mathdoc.fr/item/KYB_1967__3_4_a0/} }
Král, Jaroslav. Set-theoretical operations on $k$-multiple languages. Kybernetika, Tome 03 (1967) no. 4, p. 320. http://geodesic.mathdoc.fr/item/KYB_1967__3_4_a0/