Frontispiece of work by Peter of Spain — By Stanisław Polak (Stanislaus Polonus) - Halina Tchórzewska-Kabata, Maciej Dąbrowski (2000). Nad złoto droższe: skarby Biblioteki Narodowej (More precious than gold: treasures of the National Library). Biblioteka Narodowa. ISBN 83-70092-97-7,
Photo Credit: Public Domain, https://commons.wikimedia.org/w/index.php?curid=12844512