This rudder bar appeared in two sketches in a report on the capture of an Aviatik Berg D.I in the October 31, 1918, edition of the British aviation journal, Flight.  The 1917 blueprint below is courtesy of Koloman Mayrhofer of craftlab.at.  The photos from Hans Trauner show a restored Aviatik Berg D.I at the Technischen Museum Wein in Vienna, Austria.  The Museum of Flight in Seattle, WA, also has an original Aviatik Berg D.I.