@article{MOMA_1976__81_177750,
     author = {W.T. Patula and T.A. Burton},
     title = {Limit {Circle} {Results} for {Second} {Order} {Equations.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {185--194},
     publisher = {mathdoc},
     volume = {81},
     year = {1976},
     zbl = {0339.34028},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1976__81_177750/}
}