@article{1077472649,
author = {Wasow, Wolfgang},
title = {Asymptotic solution of boundary value problems for the differential equation $\Delta U+\lambda\frac{\partial}{\partial x} U=\lambda f(x,y)$},
journal = {Duke Math. J.},
volume = {11},
number = {1},
year = {1944},
pages = { 405-415},
language = {en},
url = {http://dml.mathdoc.fr/item/1077472649}
}
Wasow, Wolfgang. Asymptotic solution of boundary value problems for the differential equation $\Delta U+\lambda\frac{\partial}{\partial x} U=\lambda f(x,y)$. Duke Math. J., Tome 11 (1944) no. 1, pp. 405-415. http://gdmltest.u-ga.fr/item/1077472649/