Describing his novel Letters from Terra, Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the three scientists one of whom had been kidnapped by a laundryman and transported to Tartary (on Demonia, aka Antiterra, Earth's twin planet on which Ada is set, Tartary occupies the territory of the Soviet Russia):
Ada’s letters breathed, writhed, lived; Van’s Letters from Terra, ‘a philosophical novel,’ showed no sign of life whatsoever.