Habib, Laurence, og Elisabeth Juell. «Before and After Lightfoot/León. Using Rich Pictures to Illustrate an Educational Journey through the World of Opera and Ballet». FormAkademisk 7, no. 5 (desember 31, 2014). åpnet mai 17, 2022. https://journals.oslomet.no/index.php/formakademisk/article/view/679.