J. Dreybrodt & M. Laumanns (Eds.): The Unknown North of Laos. (Part 5 - 2012-2013: Karst and Caves of the Provinces Luang Nam Tha, Luang Prabang and Houaphan). - 150 pp., colour photo tables, many maps & surveys; Berlin 2013. This volume presents the results of the 2012 and 2013 International Expeditions to Northern Laos and describes a total of 27 km of passages from 95 caves, all of which are represented by a detailed survey. Includes Tham Doun Mai (3,745 m) and Tham Nam Oogh (3,140 m). In English with German and French abstracts.
 "The Unknown North of Laos. Part 5 BHB Volume 49")
