Panzer Division
History
In the early years of the Second World War the organization of the Panzer Divisions varied greatly, often according to a given unit’s seniority. In 1939-09 there were three different basic organizations for the five existing Panzer Divisions, while in 1940-05 ten divisions shared five different organizations. Generally, a lack of weapons, vehicles (tanks in particular) and equipment precluded the creation of units with the same organization and strength, thus preventing uniformity.
Sources
Panzer Divisions : The Blitzkrieg Years 1939-40 / P. Battistelli. - Oxford, 2007. -p. 15