@article{MZ_1972__125_171696,
     author = {Aiden Bruen and J. Chris Fisher},
     title = {Arcs and {Ovals} in {Derivable} {Planes.}},
     journal = {Mathematische Zeitschrift},
     pages = {122--128},
     publisher = {mathdoc},
     volume = {125},
     year = {1972},
     zbl = {0231.50013},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__125_171696/}
}