TY  - JOUR
AU  - S. Bal
TI  - Smoothness of solutions for a system of first order non-linear partial differential equations
JO  - Annales Polonici Mathematici
PY  - 1970
SP  - 41
EP  - 48
VL  - 23
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/ap-23-1-41-48/
DO  - 10.4064/ap-23-1-41-48
LA  - en
ID  - 10_4064_ap_23_1_41_48
ER  -