Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
After receiving an anonymous note, Van Veen (the narrator and main character in VN's novel Ada, 1969) tears apart his best bow tie:
According to Humbert Humbert (the narrator and main character in VN's novel Lolita, 1955), he offered Lolita (who preferred to Humbert's nonsense verse her teen-magazines) his genius:
The element that destroys Marina (in VN's novel Ada, 1969, Van's, Ada's and Lucette's mother who dies of cancer and whose body is burnt, according to her instructions) is fire:
Numbers and rows and series — the nightmare and malediction harrowing pure thought and pure time — seemed bent on mechanizing his mind. Three elements, fire, water, and air, destroyed, in that sequence, Marina, Lucette, and Demon. Terra waited.
One of the teen-magazines that Humbert Humbert (the narrator and main character in VN's novel Lolita, 1955) destroys after Lolita's abduction from the Elphinstone hospital says that unattached details take all the sparkle out of one's conversation:
In his Foreword to Shade's poem 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 two ping-pong tables that he installed in his basement:
In VN’s novel Pale Fire (1962) the poet Shade and his commentator Kinbote live in New Wye (a small University town). The Wye is a river in England and Wales. Lines Composed a Few Miles above Tintern Abbey, On Revisiting the Banks of the Wye during a Tour. July 13, 1798 is a poem by William Wordsworth (1770-1850). In Canto One of his poem Shade mentions his frame house between Goldsworth and Wordsmith on its square of green:
I cannot understand why from the lake
At the end of his commentary to Shade's poem 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) says that he may pander to the simple tastes of theatrical critics and cook up a stage play, an old-fashioned melodrama with three principals: a lunatic who intends to kill an imaginary king, another lunatic who imagines himself to be that king, and a distinguished old poet who stumbles
Describing Lucette's visit to Kingston (in VN's novel Ada, 1969, Van's American University), Van Veen (the narrator and main character in Ada) mentions The Ugly New Englander (one of the novels on the nearest bookshelf):
In her letter to Van Veen (the narrator and main character in VN's novel Ada, 1969) that Lucette (Van's and Ada's half-sister) brings to Kingston (Van's American University) Ada says that something is very wrong with the Ladore line:
According to Humbert Humbert (the narrator and main character in VN's novel Lolita, 1955), his trying to improve on Charlotte's sauces resulted in an upset stomach: