The Existence of Symmetric Designs with Parameters (189, 48, 12).

Zvonimir Janko The Existence of Symmetric Designs with Parameters (189, 48, 12). 334-338 1997 80 J. Comb. Theory, Ser. A 2 http://dx.doi.org/10.1006/jcta.1997.2806 db/journals/jct/jcta80.html#Janko97