Brzostowicz, Michał. “A CRISIS OR A NEW STAGE OF DEVELOPMENT? RESEARCH INTO THE TRANSFORMATION OF STRONGHOLD DURING THE REIGN OF THE PIAST DYNASTY IN THE 12TH AND 13TH CENTURIES, EXAMPLES OF KRUSZWICA AND LĄD NAD WARTĄ”. Slavia Antiqua. Rocznik poświęcony starożytnościom słowiańskim, no. 62 (November 8, 2021): 317–327. Accessed July 17, 2024. https://pressto.amu.edu.pl/index.php/sla/article/view/29866.