- Peter J.C. Dickinson
*An improved characterisation of the interior of the completely positive cone,*

Electron. J. Linear Algebra 20 (2010), 723-729. - M. Seetharma Gowda and R. Sznajder
*On the irreducibility, self-duality an non-homogeneity of completely positive cones.*

Electron. J. Linear Algebra 26 (2013) pp. 177-191.