Editing Pope John XXI (section)

===Bibliography===
*{{cite book |chapter=Establishing the King in his Kingdom: The Chancellor Julião Pais and his Jurists |first=Maria João |last=Branco |title=The Medieval World |editor-first1= Peter |editor-last1=Linehan |editor-first2=Janet L. |editor-last2=Nelson |publisher=Routledge  |year=2001 |page=524}}
* Guiraud, J. and L. Cadier (editors), ''Les registres de Grégoire X et de Jean XXI (1271–1277)'' (Paris, 1892–1898) [Bibliothèque de l'Ecole française à Rome, série 2, 12] (in Latin)
* Walter, Fritz, ''Die Politik der Kurie unter Gregor X'' (Berlin, 1894) (in German)
* Stapper, Richard, ''Papst Johannes XXI. Eine Monographie'' (Münster 1898) [Kirchengeschichtliche Studien, volume 4, no. 4] (in German)
* Gregorovius, Ferdinand, ''History of Rome in the Middle Ages'', volume V, part 2, second edition, revised (London: George Bell, 1906)
* H. D. Sedgwick, ''Italy in the Thirteenth Century'' Volume II (Boston-New York, 1912)
* Mazzi-Belli, V., "Pietro Hispano papa Giovanni XXI," ''Rivista di storia della medicina'' 15 (1971), 39–87 (in Italian)
* Morceau, Joseph, "Un pape portugais : Jean XXI, dénommé Pierre d'Espagne", ''Teoresi'' 24 (1979), 391–407 (in French)
* Maxwell-Stuart, P. G. ''Chronicle of the Popes: The Reign-by-Reign Record of the Papacy from St. Peter to the Present'', Thames & Hudson, 2002, p.&nbsp;119. {{ISBN|0-500-01798-0}}.
* {{EnciclopediaDeiPapi|Verfasser=José Francisco Meirinhos|ID=giovanni-xxi_(Enciclopedia-dei-Papi)/|Lemma=Giovanni XXI|Band=2|SeiteVon=|SeiteBis=|Kommentar=|kurz=}}
* {{DBI|first= José Francisco |last= Meirinho|title= Giovanni XXI, papa|url = http://www.treccani.it/enciclopedia/papa-giovanni-xxi_(Dizionario_Biografico)/ |volume= 55}}<!--leicht modifiziert gegenüber der Enciclopedia dei Papi-->
* Jean Claude Bologne: ''La Naissance Interdite; stérilité, avortement, contraception au Moyen-Age''. Orban, Paris, 1988 {{ISBN|2-85565-434-3}}.
* {{BBKL|archiveurl=https://web.archive.org/web/20070629093211/http://www.bautz.de/bbkl/j/Johannes_XXI.shtml |band=3|autor=Michael Hanst|spalten=224-228|artikel=Johannes XXI}}
* [[Joachim Telle]]: ''Petrus Hispanus in der altdeutschen Medizinliteratur und Texte unter besonderer Berücksichtigung des Thesaurus pauperum‘.'' 2 vol., Heidelberg, 1972.