@article{JRAM_1981__326_152375,
     author = {Zvonimir Janko and Tran van Trung},
     title = {Projective planes of order 12 do not have a non-abelian group of order 6 as a collineation group.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {152--157},
     publisher = {mathdoc},
     volume = {326},
     year = {1981},
     zbl = {0452.51008},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1981__326_152375/}
}