@article{MM2_1977__21_154460,
     author = {Johann Schr\"oder},
     title = {Inclusion {Statements} for {Operator} {Equations} by a {Continuity} {Principle.}},
     journal = {Manuscripta mathematica},
     pages = {135--172},
     publisher = {mathdoc},
     volume = {21},
     year = {1977},
     zbl = {0363.65050},
     url = {http://geodesic.mathdoc.fr/item/MM2_1977__21_154460/}
}