Autorités BnF, data.bnf.fr, besøkt 10. oktober 2015[Hentet fra Wikidata]
britannica.com
Encyclopædia Britannica Online, oppført som Sir John Gielgud, Encyclopædia Britannica Online-ID biography/John-Gielgud, besøkt 9. oktober 2017[Hentet fra Wikidata]
RADA Student & graduate profiles, www.rada.ac.uk[Hentet fra Wikidata]
theshakespeareblog.com
«One-man shows and Shakespeare’s theatre | The Shakespeare blog»(engelsk). The Shakespeare Blog. 2. september 2011. Besøkt 7. april 2020. «The idea for Gielgud to put on his own Shakespeare performance came from his great-aunt, Ellen Terry, easily the most famous actress of the late nineteenth century. When she became too old to play them onstage, she performed extracts from her famous roles in Shakespeare’s Heroines.»