@misc{Balbus_Ioannes_Summa,,
 author={Balbus, Ioannes},
 howpublished={online},
 publisher={Koberger, Anton},
 language={lat},
 type={inkunabuły},
 title={Summa, que vocatur Catholicon edita a fratre Iohanne de Ianna ordinis fratrum predicator. Pars 1-4},
}