Gąssowski, Jerzy. Poszukiwanie grobu Kopernika // www.astronomia.pl. Grupa Astronomia, 2005. Архивиран от оригинала на 8 юли 2014. Посетен на 7 декември 2017. It results from the research of Dr. Jerzy Sikorski, an Olsztyn historian and an outstanding researcher of the life and work of Nicolaus Copernicus. According to Dr. Sikorski, the canon of the Frombork cathedral was buried in the immediate vicinity of this altar, which was entrusted to their care. This altar was the one who once wore the call of Saint Andrew, and now St. Cross, fourth in the right row. (на полски)
Gąssowski, Jerzy. Poszukiwanie grobu Kopernika // www.astronomia.pl. Grupa Astronomia, 2005. Архивиран от оригинала на 8 юли 2014. Посетен на 7 декември 2017. It results from the research of Dr. Jerzy Sikorski, an Olsztyn historian and an outstanding researcher of the life and work of Nicolaus Copernicus. According to Dr. Sikorski, the canon of the Frombork cathedral was buried in the immediate vicinity of this altar, which was entrusted to their care. This altar was the one who once wore the call of Saint Andrew, and now St. Cross, fourth in the right row. (на полски)