http://karmapaissue.files.wordpress.com/2013/05/affirm-geoffrey-samuel.pdf Tulku Urgyen accounts this as well in "Blazing Splendor", Rangjung Yeshe Publ. 2005, P. 59ff. See also: Brown, Mick: The Dance of 17 Lives: The Incredible True Story of Tibet's 17th Karmapa. Bloomsbury Publishing, 2004 pg. 38/39 and Wong, Sylvia: The Karmapa Prophecies, Delhi 2010, pg. 2 and 370. Tenga Rinpoche says in an interview, that these events are mentioned in the biography of the 15th Karmapa, written by a teacher of the 16th Karmapa, Jamgön Kongtrül Khyentse Öser, without naming the "minister" by name (Interview mit Tenga Rinpoche, in: Dharmanektar Nr.3/89).
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tibet.prm.ox.ac.uk
Staff. "Lungshar Biography". The Tibet Album. Retrieved 2010-02-04. Hosted at tibet.prm.ox.ac.uk.