@article{MZ_1986__193_173780,
     author = {C.Y. Ho},
     title = {Involutory {Collineations} of {Finite} {Planes.}},
     journal = {Mathematische Zeitschrift},
     pages = {235--240},
     publisher = {mathdoc},
     volume = {193},
     year = {1986},
     zbl = {0599.51010},
     url = {http://geodesic.mathdoc.fr/item/MZ_1986__193_173780/}
}