Casanova, Gertrude. St. Walburga. The Catholic Encyclopedia. Vol. 15. New York: Robert Appleton Company, 1912; online: https://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/St._Walburga (abgerufen am 7. Juni 2018): „In the Roman Martyrology she is commemorated on 1 May, […]; sometimes she is represented in a group with St. Philip and St. James the Less, and St. Sigismund, King of Burgundy, because she is said to have been canonized by Pope Adrian II on 1 May, the festival of these saints.“ („she is said“ = keine gesicherte Information).
Casanova, Gertrude. St. Walburga. The Catholic Encyclopedia. Vol. 15. New York: Robert Appleton Company, 1912; online: https://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/St._Walburga (abgerufen am 7. Juni 2018): „About 870, Otkar, then Bishop of Eichstadt, determined to restore the church and monastery of Heidenheim, which were falling to ruin. The workmen having desecrated St. Walburga's grave, […].“ – Die Umbettung soll nach der genannten Quelle dann aber erst am 21. September des gleichen Jahres erfolgt sein: „she one night appeared to the bishop, reproaching and threatening him. This led to the solemn translation of the remains to Eichstadt on 21 Sept. of the same year.“
