Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
On Admiral Tobakoff Lucette (in VN's novel Ada, 1969, Van's and Ada's half-sister) calls one of the passengers, a tall mulatto girl, “Miss Condor” (a play on con d’or):
Describing a stage performance in which Marina (in VN’s novel Ada, 1969, Van's, Ada's and Lucette's mother) played the heroine, Van Veen mentions an old nurse in Eskimo's boots:
The action in VN's novel Ada (1969) takes place on Demonia, Earth's twin planet also known as Antiterra. After the L disaster in the beau milieu of the 19th century electricity was banned on Antiterra:
Describing his life in Paris in the 1920s and 1930s, Vadim Vadimovich (the narrator and main character in VN's novel Look at the Harlequins!, 1974) mentions Vasiliy Sokolovski, the writer who since the dawn of the century had been devoting volume after volume to the mystical and social history of a Ukrainian clan that had started as a humble family of three in the sixteenth century but by volume six (1920) had become a whole village, replete with folklore and myth:
One of the three main characters in VN's novel Pale Fire (1962), Kinbote (Shade's mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla) nicknamed his black gardener “Balthasar, Prince of Loam:”
Describing the difference between Terra and Antiterra (aka Demonia, Earth’s twin planet on which Ada is set), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the deepest thinkers, the purest philosophers, Paar of Chose and Zapater of Aardvark:
Describing Shade's murder by Gradus, Kinbote (in VN's novel Pale Fire, 1962, Shade's mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla) quotes a line from Matthew Arnold's poem The Scholar-Gipsy (1853):
According to Kinbote (in VN’s novel Pale Fire, 1962, Shade’s mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla), New Wye (a small University town) is situated at the same latitude as Palermo:
One of Countess de Fyler's two daughters, Fleur de Fyler (in VN's novel Pale Fire, 1962, Queen Disa's favorite lady-in-waiting) sleeps in a patifolia (a huge, oval, luxuriously flounced, swansdown pillow the size of a triple bed that Charles Xavier had installed in the middle of the Persian rug-covered floor):
Describing the forty days between Queen Blenda's death and his coronation, Kinbote (in VN's novel Pale Fire, 1962, Shade’s mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla) mentions a so-called patifolia (a huge, oval, luxuriously flounced, swansdown pillow the size of a triple bed) that Charles Xavier had installed in the middle of the Persian rug-covered floor: