@article{01283602, title = {Eigenvalues of boundary value problems for higher-order differential equations.}, journal = {Mathematical Problems in Engineering}, volume = {2}, year = {1996}, pages = {401-434}, doi = {10.1155/S1024123X96000415}, zbl = {0921.34021}, language = {en}, url = {http://dml.mathdoc.fr/item/01283602} }
Wong, Patricia J.Y.; Agarwal, Ravi P. Eigenvalues of boundary value problems for higher-order differential equations.. Mathematical Problems in Engineering, Tome 2 (1996) pp. 401-434. doi : 10.1155/S1024123X96000415. http://gdmltest.u-ga.fr/item/01283602/