GÓRCZYK, W. J. Najstarsze pieczęcie Ciechanowa. Studia Mazowieckie, [S. l.], v. 17, n. 1, p. 79–92, 2022. DOI: 10.54539/sm.25. Disponível em: https://studiamazowieckie.puzim.edu.pl/index.php/sm/article/view/25. Acesso em: 21 grudz. 2024.