@article{NUMA_1976__26_132425,
     author = {J. Sprekels},
     title = {Existenz und erste {Einschlie{\ss}ung} positiver {L\"osungen} bei superlinearen {Randwertaufgaben} zweiter {Ordnung.}  {-Existence} and {First} {Bounds} of {Positive} {Solutions} of {Superlinear} {Second-Order} {Boundary} {Value} {Problems.}},
     journal = {Numerische Mathematik},
     pages = {421--428},
     publisher = {mathdoc},
     volume = {26},
     year = {1976},
     zbl = {0345.65044},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1976__26_132425/}
}