@article{IM2_1969_3_6_a9,
     author = {V. Sh. Burd and Yu. S. Kolesov and M. A. Krasnosel'skii},
     title = {On the existence and constancy of sign of {Green's} function of scalar equations of high order with almost periodic coefficients},
     journal = {Izvestiya. Mathematics },
     pages = {1319--1334},
     publisher = {mathdoc},
     volume = {3},
     number = {6},
     year = {1969},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1969_3_6_a9/}
}