@article{JDM_1957__59_146424,
     author = {Helmut Schaefer},
     title = {\"Uber die {Methode} sukzessiver {Approximationen.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {131--140},
     publisher = {mathdoc},
     volume = {59},
     year = {1957},
     zbl = {0077.11002},
     url = {http://geodesic.mathdoc.fr/item/JDM_1957__59_146424/}
}