@article{702178,
     title = {Elliptic partial differential equations and ordinary differential equations in Banach space},
     booktitle = {Differential Equations and Their Applications},
     series = {GDML\_Books},
     publisher = {Publishing House of the Czechoslovak Academy of Sciences},
     address = {Prague},
     year = {1963},
     pages = {121-122},
     mrnumber = {MR0168940},
     zbl = {0125.05803},
     url = {http://dml.mathdoc.fr/item/702178}
}

Nirenberg, L. Elliptic partial differential equations and ordinary differential equations in Banach space, dans Differential Equations and Their Applications, GDML_Books,  (1963), pp. 121-122. http://gdmltest.u-ga.fr/item/702178/