Universally optimal matrices and field independence of the minimum rank of a graph. Dealba, Luz M.; Grout, Jason; Hogben, Leslie; Mikkelson, Rana; Rasmussen, Kaela — 2009 ELA. The Electronic Journal of Linear Algebra [electronic only]
Minimum rank of a tree over an arbitrary field. Chenette, Nathan L.; Droms, Sean V.; Hogben, Leslie; Mikkelson, Rana; Pryporova, Olga — 2007 ELA. The Electronic Journal of Linear Algebra [electronic only]