no. 2
A simple proof of Valiant's lemma
RAIRO. Informatique théorique et applications, Tome 20 (1986) no. 2, pp. 183-190 
@article{ITA_1986__20_2_183_0,
     author = {Walter, Hermann K.-G.},
     title = {A simple proof of {Valiant's} lemma},
     journal = {RAIRO. Informatique th\'eorique et applications},
     pages = {183--190},
     year = {1986},
     publisher = {AFCET - Gauthier-Villars},
     address = {Paris},
     volume = {20},
     number = {2},
     mrnumber = {860768},
     zbl = {0606.68075},
     language = {en},
     url = {https://www.numdam.org/item/ITA_1986__20_2_183_0/}
}
TY  - JOUR
AU  - Walter, Hermann K.-G.
TI  - A simple proof of Valiant's lemma
JO  - RAIRO. Informatique théorique et applications
PY  - 1986
SP  - 183
EP  - 190
VL  - 20
IS  - 2
PB  - AFCET - Gauthier-Villars
PP  - Paris
UR  - https://www.numdam.org/item/ITA_1986__20_2_183_0/
LA  - en
ID  - ITA_1986__20_2_183_0
ER  - 
%0 Journal Article
%A Walter, Hermann K.-G.
%T A simple proof of Valiant's lemma
%J RAIRO. Informatique théorique et applications
%D 1986
%P 183-190
%V 20
%N 2
%I AFCET - Gauthier-Villars
%C Paris
%U https://www.numdam.org/item/ITA_1986__20_2_183_0/
%G en
%F ITA_1986__20_2_183_0
Walter, Hermann K.-G. A simple proof of Valiant's lemma. RAIRO. Informatique théorique et applications, Tome 20 (1986) no. 2, pp. 183-190. https://www.numdam.org/item/ITA_1986__20_2_183_0/

1. M. A. Harrison, Introduction to Formal Languages Theory, Addison-Wesley Pub. Co., Reading, Mass. 1978. | Zbl | MR

2. L. Valiant, General Context-free Recognition In Less Than Cubic Time, J. Comp. Syst. Sc., Vol. 10, 1975, pp. 308-315. | Zbl | MR