Stamp-edition for the Sino-Swedish Expedition in China 1927-1933 (China: Michel-No. 246 - 249).
Sven Hedin Foundation, Stockholm. <a rel="nofollow" class="external autonumber" href="http://www.etnografiska.se/smvk/road/www/article/10/jsp/Render.jsp?t=99&amp;a=6731&amp;l=en_US">[2]</a>
CC BY 2.5
Sven Hedin Foundation, Stockholm.  <a rel="nofollow" class="external autonumber" href="http://www.etnografiska.se/smvk/road/www/article/10/jsp/Render.jsp?t=99&amp;a=6731&amp;l=en_US">[1]</a>