@misc{Piotr_z_Krakowa_Petri,
 author={Piotr z Krakowa},
 howpublished={online},
 language={lat},
 type={starodruk},
 title={Petri Cracoviensis computus ecclesiasticus vel astronomicus universis scholasticis et viris ecclesiasticis non minus utilis atque necessarius},
 keywords={astronomia 16w.},
}