Tamm, Eric Enno. "The Horse That Leaps Through Clouds: A Tale of Espionage, the Silk Road and the Rise of Modern China," (2010) p. 3, http://horsethatleaps.com
Tamm, Eric Enno. "The Horse That Leaps Through Clouds: A Tale of Espionage, the Silk Road and the Rise of Modern China," (2010) p. 353, http://horsethatleaps.com