"The Papers of Martin Luther King, Jr., Volume IV: Symbol of the Movement, January 1957-December 1958". Book by Martin Luther King, Clayborne Carson, Peter Holloran, Ralph Luker, Penny A. Russell (University of California Press), p. 211, 1992.
Ernest Bramah (2016). “THE KAI LUNG FANTASY SERIES: The Wallet of Kai Lung, Kai Lung's Golden Hours & Kai Lung Unrolls His Mat: The Transmutation of Ling, The Story of Yung Chang, The Probation of Sen Heng, The Experiment of the Mandarin Chan Hung, The Confession of Kai Lung, The Vengeance of Tung Fel and more”, p.126, e-artnow
Ernest Bramah (2016). “THE KAI LUNG FANTASY SERIES: The Wallet of Kai Lung, Kai Lung's Golden Hours & Kai Lung Unrolls His Mat: The Transmutation of Ling, The Story of Yung Chang, The Probation of Sen Heng, The Experiment of the Mandarin Chan Hung, The Confession of Kai Lung, The Vengeance of Tung Fel and more”, p.154, e-artnow