In the unofficial sequel to the 1939 film, operatic mezzo-soprano Risë Stevens provides the voice of "Glinda, the Good Fairy" as she is described in the opening title sequence (however, the Cowardly Lion refers to her as the Good Witch of the North later in the film. In L. Frank Baum's novel, "The Lost Princess of Oz", the Wizard says: "Ozma is a fairy, and so is Glinda, so no power can kill or destroy them, but you girls are all mortals and so are Button-Bright and I, so we must watch out for ourselves." However, the only fact established by this statement is that Glinda is one of Oz's "fairy people" (L. Frank Baum's term for anyone native to an enchanted land) rather than a Fairy proper. Even the citizens of Oz who do not possess magical powers are referred to as "fairy people" by Baum in "The Emerald City of Oz", meaning that they are not mortals like Dorothy and the Wizard who were born in the outside world.