On the essential spectrum of elliptic differential operators
2018 ◽
Vol 468
(2)
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pp. 839-864
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1998 ◽
Vol 58
(2)
◽
pp. 213-221
◽
1994 ◽
Vol 74
(1)
◽
pp. 107-128
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1999 ◽
Vol 6
(2)
◽
pp. 207-225
◽
2017 ◽
Vol 451
(1)
◽
pp. 473-496
◽
1976 ◽
Vol 74
◽
pp. 239-252
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