it's difficult to find too much material, but this here is a good start:
http://www.ibiblio.org/hyperwar//AAF/USSBS/ETO-Summary.html#tgwe
The German War Economy
Study of German war production data as well as interrogation of those who were in charge of rearmament at the time, leaves no doubt that until the defeat at Moscow German industry was incompletely mobilized and that in fact Germany did not foresee the need for full economic mobilization. German arms production during 1940 and 1941 was generally below that of Britain. When the full meaning of the reverses at Moscow became apparent the German leaders called for all-out production. The conquests of the previous years had greatly strengthened Germany's economy; with the exception of oil and rubber, supplies of virtually all the previously scarce imported materials were or had become accessible. Great reserves of foreign labor only awaited voluntary or forced recruitment. The industrial plant of France, the Low Countries, Poland and Czechoslovakia had been added to that of Germany. After the defeat at Moscow early in 1942, armament production increased rapidly. However, such increase was more the result of improvements in industrial efficiency than of general economic mobilization. Studies of German manpower utilization show that throughout the war a great deal of German industry was on a single shift basis, relatively few German women (less than in the first war) were drawn into industry and the average work week was below British standards.
Germany's early commitment to the doctrine of the short war was a continuing handicap; neither plans nor state of mind were adjusted to the idea of a long war. Nearly all German sources agree that the hope for a quick victory lasted long after the short war became a long one. Germany's armament minister Albert Speer, who assumed office in early 1942, rationalized German war production and eliminated the worst inefficiencies in the previous controls. A threefold increase in armament production occurred under his direction but the increase cannot be considered a testament to the efficiency of dictatorship. Rather it suggests the degree of industrial undermobilization in the earlier years. An excellent case can be made that throughout the war top government management in Germany was not efficient.
http://www.ibiblio.org/hyperwar//AAF/USSBS/ETO-Summary.html#tgwe
The German War Economy
Study of German war production data as well as interrogation of those who were in charge of rearmament at the time, leaves no doubt that until the defeat at Moscow German industry was incompletely mobilized and that in fact Germany did not foresee the need for full economic mobilization. German arms production during 1940 and 1941 was generally below that of Britain. When the full meaning of the reverses at Moscow became apparent the German leaders called for all-out production. The conquests of the previous years had greatly strengthened Germany's economy; with the exception of oil and rubber, supplies of virtually all the previously scarce imported materials were or had become accessible. Great reserves of foreign labor only awaited voluntary or forced recruitment. The industrial plant of France, the Low Countries, Poland and Czechoslovakia had been added to that of Germany. After the defeat at Moscow early in 1942, armament production increased rapidly. However, such increase was more the result of improvements in industrial efficiency than of general economic mobilization. Studies of German manpower utilization show that throughout the war a great deal of German industry was on a single shift basis, relatively few German women (less than in the first war) were drawn into industry and the average work week was below British standards.
Germany's early commitment to the doctrine of the short war was a continuing handicap; neither plans nor state of mind were adjusted to the idea of a long war. Nearly all German sources agree that the hope for a quick victory lasted long after the short war became a long one. Germany's armament minister Albert Speer, who assumed office in early 1942, rationalized German war production and eliminated the worst inefficiencies in the previous controls. A threefold increase in armament production occurred under his direction but the increase cannot be considered a testament to the efficiency of dictatorship. Rather it suggests the degree of industrial undermobilization in the earlier years. An excellent case can be made that throughout the war top government management in Germany was not efficient.
