Pilcher, Frederick (October 2010), "Rotation Period Determinations for 80 Sappho, 145 Adeona, 217 Eudora, 274 Philagoria, 567 Eleutheria, and 826 Henrika", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, 37 (4): 148–149, Bibcode:2010MPBu...37..148P.