@article{1077465458,
author = {Kaufman, H. and Sternberg, R. L.},
title = {A two-point boundary problem for ordinary self-adjoint
differential equations of even order},
journal = {Duke Math. J.},
volume = {20},
number = {1},
year = {1953},
pages = { 527-531},
language = {en},
url = {http://dml.mathdoc.fr/item/1077465458}
}
Kaufman, H.; Sternberg, R. L. A two-point boundary problem for ordinary self-adjoint
differential equations of even order. Duke Math. J., Tome 20 (1953) no. 1, pp. 527-531. http://gdmltest.u-ga.fr/item/1077465458/