John Buchan (2016). “MYSTERY & ESPIONAGE Ultimate Collection – Complete Richard Hannay, Dickson McCunn & Sir Edward Leithen Series in One Premium Edition: The Greatest Tales of Mystery, Espionage & Nail-Biting Suspense: The Thirty-Nine Steps, Greenmantle, The Three Hostages, Huntingtower, The Power-House, The Gap in the Curtain and many more”, p.2890, e-artnow