Mickel & Nelson 1977, p. lxxxxi (Elioxe ed. Mickel Jr., Béatrix ed. Nelson) Mickel, Emanuel J.; Nelson, Jan A., eds. (1977). La Naissance du Chevalier au Cygne(preview). The Old French Crusade Cycle. Vol. 1. Geoffrey M. Myers (essay). University of Alabama Press. ISBN9780817385019. (Elioxe ed. Mickel Jr., Béatrix ed. Nelson)
Mickel & Nelson 1977, Myer's essay, p.lxxxxi- Mickel, Emanuel J.; Nelson, Jan A., eds. (1977). La Naissance du Chevalier au Cygne(preview). The Old French Crusade Cycle. Vol. 1. Geoffrey M. Myers (essay). University of Alabama Press. ISBN9780817385019. (Elioxe ed. Mickel Jr., Béatrix ed. Nelson)
Gerritsen & Van Melle 1998, Dictionary of Medieval Heroes, reprinted 2000, pp.247 "Seven Sages of Rome" Gerritsen, Willem Pieter; Van Melle, Anthony G. (1998). Dictionary of Medieval Heroes: Characters in Medieval Narrative Traditions and Their Afterlife in Literature, Theatre and the Visual Arts. Boydell Press. Reprint: Boydell & Brewer 2000. ISBN0851157807, 9780851157801 (preview)
Mickel & Nelson 1977, Myer's essay, p.xciii- Mickel, Emanuel J.; Nelson, Jan A., eds. (1977). La Naissance du Chevalier au Cygne(preview). The Old French Crusade Cycle. Vol. 1. Geoffrey M. Myers (essay). University of Alabama Press. ISBN9780817385019. (Elioxe ed. Mickel Jr., Béatrix ed. Nelson)
doi.org
"Die Erzählung von den Schwanenkindern stellt eine frühe Vorform von AaTh/ATU 451 "Mädchen sucht seine Brüder dar" [The Tale of the Swan Children is an early form of ATU 451, "The Maiden Who Seeks Her Brothers"]. Ehrismann, Otfrid. "Schwan(en)ritter" [Swan Knight]. In: Enzyklopädie des Märchens Online. Edited by Rolf Wilhelm Brednich, Heidrun Alzheimer, Hermann Bausinger, Wolfgang Brückner, Daniel Drascek, Helge Gerndt, Ines Köhler-Zülch, Klaus Roth and Hans-Jörg Uther. Berlin, Boston: De Gruyter, 2016 [2007]. p. 299. https://doi.org/10.1515/emo.12.070