Stable Subspaces of Positive Maps of Matrix Algebras. - Marek Miller; Robert Olkiewicz (Open Syst. Inf. Dyn., 2015)

Extremal Positive Maps on M3(ℂ) and Idempotent Matrices. - Marek Miller; Robert Olkiewicz (Open Syst. Inf. Dyn., 2016)

On Extremal Positive Maps of Three-Dimensional Matrix Algebra. - Piotr Lugiewicz; Robert Olkiewicz (Open Syst. Inf. Dyn., 2021)

On a New Family of Extremal Positive Maps of Three-Dimensional Matrix Algebra. - Piotr Lugiewicz; Robert Olkiewicz (Open Syst. Inf. Dyn., 2021)