Look on page 154 of Jeff Nolls book. The J.R.99 is listed as being part of the 30.J.D. or 30 Infantry Division.
The book "Histories of 251 Divisions of the German Army Which Participated in the War, 1914-1918; describes the World War I battle history of the 30th Infantry Division. It battled on the Western Front during World War I. During 1916 it saw action at titanic battles of Verdun and the Somme. Up until 1917 it was considered a first class shock unit.