SPECTRAL PROPERTIES AND DISTRIBUTION OF EIGENVALUES OF NON–SELF-ADJOINT ELLIPTIC DIFFERENTIAL OPERATORS
1998 ◽
Vol 58
(2)
◽
pp. 213-221
◽
1994 ◽
Vol 74
(1)
◽
pp. 107-128
◽
1999 ◽
Vol 6
(2)
◽
pp. 207-225
◽