TY  - JOUR
AU  - Mencherini, Lorenzo
TI  - A simple necessary and sufficient condition for well-posedness of $2 \times 2$ differential systems with time-dependent coefficients
JO  - Bollettino della Unione matematica italiana
PY  - 2006
SP  - 215
EP  - 220
VL  - 9B
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/BUMI_2006_8_9B_1_a10/
LA  - en
ID  - BUMI_2006_8_9B_1_a10
ER  -