Geodesic
There does not exist an enumerable family of context-free grammars that generates the class of single-valued languages
Matematičeskie zametki, Tome 50 (1991) no. 1, pp. 34-40.

Voir la notice de l'article provenant de la source Math-Net.Ru

@article{MZM_1991_50_1_a3,
     author = {K. Yu. Gorbunov},
     title = {There does not exist an enumerable family of context-free grammars that generates the class of single-valued languages},
     journal = {Matemati\v{c}eskie zametki},
     pages = {34--40},
     publisher = {mathdoc},
     volume = {50},
     number = {1},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1991_50_1_a3/}
}
TY  - JOUR
AU  - K. Yu. Gorbunov
TI  - There does not exist an enumerable family of context-free grammars that generates the class of single-valued languages
JO  - Matematičeskie zametki
PY  - 1991
SP  - 34
EP  - 40
VL  - 50
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1991_50_1_a3/
LA  - ru
ID  - MZM_1991_50_1_a3
ER  - 
%0 Journal Article
%A K. Yu. Gorbunov
%T There does not exist an enumerable family of context-free grammars that generates the class of single-valued languages
%J Matematičeskie zametki
%D 1991
%P 34-40
%V 50
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1991_50_1_a3/
%G ru
%F MZM_1991_50_1_a3
K. Yu. Gorbunov. There does not exist an enumerable family of context-free grammars that generates the class of single-valued languages. Matematičeskie zametki, Tome 50 (1991) no. 1, pp. 34-40. http://geodesic.mathdoc.fr/item/MZM_1991_50_1_a3/