Results and problems in the spectral theory of periodic differential equations
1975 ◽
pp. 126-135
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2010 ◽
Vol 164
(5)
◽
pp. 659-841
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2011 ◽
Vol 250
(11)
◽
pp. 4177-4199
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1994 ◽
Vol 187
(2)
◽
pp. 339-351
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2006 ◽
Vol 15
(3)
◽
pp. 703-723
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2011 ◽
Vol 250
(2)
◽
pp. 1232-1233
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