Editors. "Henrik Hop leads a further expedition beyond Orange River". The Literary Encyclopedia. First published 30 December 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=17766, accessed 20 May 2013.]
In South Africa, Henrik Hop leads a further expedition beyond the Orange River, which had been explored by Jacobus Coetsee the previous year.