@Book{069613273,
author="Hellstr{\"o}m, Pontus
and Langballe, Hans",
title="rock drawings",
series="The Scandinavian joint expedition to Sudanese Nubia",
year="1970",
address="Stockholm",
note="Pontus Hellstr{\"o}m in collab. with Hans Langballe. Including the results of The Gordon Memorial College Expedition to Abka under the dir. of Oliver Myers. With a general introd. by Torgny S{\"a}ve-S{\"o}derbergh",
language="English"
}