@article{AM2_1968__1_135996,
     author = {J.F. Rigby},
     title = {Collineations on {Quadrilaterals} in {Projective} {Planes.} {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {318--320},
     year = {1968},
     volume = {1},
     url = {http://geodesic.mathdoc.fr/item/AM2_1968__1_135996/}
}