@inbook{400401, title = {VI. Nonlinear boundary value problems (Perturbation theory)}, booktitle = {Differential and Integral Equations}, series = {GDML\_Books}, publisher = {Academia}, address = {Praha}, year = {1979}, pages = {209-238}, url = {http://dml.mathdoc.fr/item/400401} }
(éd.). VI. Nonlinear boundary value problems (Perturbation theory), dans Differential and Integral Equations, GDML_Books, (1979), pp. 209-238. http://gdmltest.u-ga.fr/item/400401/