Boundary value problems for real linear partial differential equations of first order
1997 ◽
Vol 49
(11)
◽
pp. 1659-1670
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1989 ◽
Vol 11
(3-4)
◽
pp. 173-183
◽
1964 ◽
Vol 19
(3)
◽
pp. 1-51
◽
2008 ◽
Vol 19
(3)
◽
pp. 211-233
◽