Andrei Babikov's edition of Nabokov's correspondence with his friend Mikhail Karpovich, the Harvard historian of Russia, edited, with full notes, from originals in the Nabokov archive of the Berg Collection at the New York Public Library, the Nabokov papers in the Library of Congress, and the Bakhmeteff Archive at Columbia, has recently been published in Russian:
Nabokov, Vladimir. Perepiska s Mikhaylom Karpovichem: 1933-1959. Ed. Andrei A. Babikov. Moscow: Litfakt, 2018. 160pp., ill. ISBN 978-5-9500994-0-3.
Nabokov's letters all appear in full, as do some from Karpovich, with others being quoted in the introduction and notes.