Scientific examination of classic Spanish stamps with colour error, a non-invasive micro-Raman and micro-XRF approach: The King Alfonso XIII (1889–1901 “Pelón”) 15 cents definitive issue.
Richard A. Engelhardt (Editor-in-Chief), Asia Conserved: Lessons Learned from the UNESCO Asia-Pacific Heritage Awards for Culture Heritage Conservation (2000–2004), ISBN: 92-9223-117-0, Published in August 2007 by UNESCO Bangkok, Printed by Clung Wicha Press Co., Ltd., 440 pp.