@article{KJM_2010_34_1_a9,
     author = {Adegoke S. A. Osifodunrin},
     title = {On the existence of (196,91,42) {Hadamard} difference sets},
     journal = {Kragujevac Journal of Mathematics},
     pages = {113 - 130},
     publisher = {mathdoc},
     volume = {34},
     number = {1},
     year = {2010},
     url = {http://geodesic.mathdoc.fr/item/KJM_2010_34_1_a9/}
}