Freza‑Olczyk, Mariola. 2019. „Stepmother and Stepson: Duchess Matilda in the Power Struggle After the Death of Her Husband Barnim I, the Duke of Pomerania”. Studia Z Dziejów Średniowiecza, nr 23 (grudzień):83-99. https://doi.org/10.26881/sds.2019.23.03.