On the polynomial numerical hull of a normal matrix. Afshin, Hamid Reza; Mehrjoofard, Mohammad Ali — 2011 Banach Journal of Mathematical Analysis [electronic only]
Polynomial numerical hulls of order 3. Afshin, Hamid Reza; Mehrjoofard, Mohammad Ali; Salemi, Abbas — 2009 ELA. The Electronic Journal of Linear Algebra [electronic only]