TY  - JOUR
AU  - Yu. B. Orochko
TI  - Impenetrability condition for a~degenerate point of a~one-term  symmetric differential operator of even order
JO  - Sbornik. Mathematics
PY  - 2003
SP  - 745
EP  - 774
VL  - 194
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_2003_194_5_a4/
LA  - en
ID  - SM_2003_194_5_a4
ER  -