Greig Malcolm (2006). „On the coexistence of conference matrices and near resolvable 2-(2k+1,k,k-1) designs”. Journal of Combinatorial Theory, Series A113, 703–711. o. DOI:10.1016/j.jcta.2005.05.005.
Gropp Harald (2004). „More on orbital matrices”. Electronic Notes in Discrete Mathematics17, 179–183. o. DOI:10.1016/j.endm.2004.03.036.