Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
According to Ada (the title character in a novel, 1969, by VN), at Marina's funeral Demon and d'Onsky's son, a person with only one arm, wept comme des fontaines:
‘My upper-lip space feels indecently naked.’ (He had shaved his mustache off with howls of pain in her presence). ‘And I cannot keep sucking in my belly all the time.’
In VN’s novel Ada (1969) Van Veen (the narrator and main character) paraphrases the lines in Lermontov’s poem The Demon (1829-40), replacing “the summits of the Caucasus” with “the summits of the Tacit” and “Kazbek” with “Mount Peck:”
Describing the torments of poor mad Aqua (the twin sister of Van's, Ada's and Lucette's mother Marina), Van Veen (the narrator and main character in VN's novel Ada, 1969) says that the human brain can become the best torture house of all those it has invented, established and used in millions of years, in millions of lands, on millions of howling creatures:
In VN's play Izobretenie Val'sa ("The Waltz Invention," 1938) the Minister of War tells Waltz that he wants to buy Waltz's Telethanasia and uses the phrase priobretenie vashego izobreteniya (the acquisition of your invention):
Министр. Скучно, обидно. Придется завербовать ученых... пускай как-нибудь объяснят... (Заметив Вальса.) А, вот он. Здравствуйте. Присаживайтесь. Господа, занимайте места. Заседание продолжается. Итак... Полковник!
Полковник. Чего изволите?
In VN's novel Camera Obscura (1933) translated into English as Laughter in the Dark (1938) Robert Horn (Axel Rex in LITD) tells Bruno Kretschmar (Albert Albinus in LITD) that death is merely a bad habit:
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), both Andronnikov and Niagarin (the two Soviet experts whom the new Zemblan government hired to find the crown jewels) are conspicuously bandy-legged:
In 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) calls his uncle Conmal (Shakespeare’s translator into Zemblan) “the venerable Duke:”
In a conversation at the Faculty Club 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 kinbote means in Zemblan "a king's destroyer" and longs to explain that a king who sinks his identity in the mirror of exile is in a sense just that:
Professor Pardon now spoke to me: "I was under the impression that you were born in Russia, and that your name was a kind of anagram of Botkin or Botkine?"
In 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 exile becomes a bad habit:
Line 998: Some neighbor's gardener
When Van and Ada climb the shattal tree (the Tree of Knowledge that grows at Ardis), Ada mentions l’ardeur de la canicule (the extreme heat of summer):