@misc{Johannes_de_Sacrobosco_(ca_1195-1256)_Ioannis,
 author={Johannes de Sacrobosco (ca 1195-1256)},
 howpublished={online},
 publisher={Jan Haller},
 type={starodruk},
 title={Ioannis De Sacrobosco Astronomi celeberrimi sphericu[m] opusculum},
}