TY  - JOUR
AU  - A. Pilś
TI  - The characteristic equation for partial differential equations of the first order
JO  - Colloquium Mathematicum
PY  - 1958
SP  - 223
EP  - 226
VL  - 6
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/cm-6-1-223-226/
DO  - 10.4064/cm-6-1-223-226
LA  - en
ID  - 10_4064_cm_6_1_223_226
ER  -