@misc{Helias_Petrus_(ca_1100-1166?)_Grammatica,
 author={Helias, Petrus (ca 1100-1166?)},
 howpublished={online},
 publisher={Martin Flach},
 language={lat},
 type={inkunabuł},
 title={Grammatica cum commento Ioannis Sommerfeld},
 keywords={inkunabuły 15 w.},
}