Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
The characters in VN’s novel Zashchita Luzhina (“The Luzhin Defense,” 1930) include Valentinov, Luzhin’s tutor and manager whom Luzhin’s father, the writer, wants to use in his new book:
In Canto Three of his poem John Shade (the poet in VN’s novel Pale Fire, 1962) wonders if he should stop investigating his abyss and mentions a web of sense:
Life Everlasting – based on a misprint!
I mused as I drove homeward: take the hint,
And stop investigating my abyss?
But all at once it dawned on me that this
Was the real point, the contrapuntal theme;
In Canto Three of his poem John Shade (the poet in VN’s novel Pale Fire, 1962) describes his heart attack and mentions a story in a magazine about a Mrs. Z. whose heart had been rubbed back to life by a prompt surgeon's hand:
It was a story in a magazine
About a Mrs. Z. whose heart had been
Rubbed back to life by a prompt surgeon's hand.
She told her interviewer of "The Land
In VN’s novel Ada (1969) Marina (Van’s, Ada’s and Lucette’s mother) likes to have her hair done in the open so as to forestall the zephyrs:
Describing King Victor’s last visit to Villa Venus (Eric Veen’s floramors), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions an ironic Hesperus that rose in a milkman’s humdrum sky:
Describing King Victor’s last visit to Villa Venus (Eric Veen’s floramors), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions a line composed by Seneca that King Victor wrote in the Shell Pink Book:
In VN’s novel Ada (1969) Van and Ada find out that they are brother and sister thanks to Marina’s old herbarium that they discovered in the attic of Ardis Hall:
Describing Villa Venus (Eric Veen’s floramors), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the architect’s nephew and heir, an honest but astoundingly stuffy clothier in Ruinen:
Describing the suicide of poor mad Aqua (the twin sister of his, Ada’s and Lucette’s mother Marina), Van Veen (the narrator and main character in VN’s novel Ada, 1969) compares Aqua to a Russian country girl lakomyashchayasya yagodami (feasting on berries):
In his farewell letter to Marina (in VN’s novel Ada, 1969, Van’s, Ada’s and Lucette’s mother) Demon Veen (Van's and Ada's father) mentions his crumpled wings: