BIBLIOGRAPHY:
Books written specifically about the 756th Tank Battalion:

The 756th Tank Battalion at the Battle of Cassino
by Roger Fazendin
(1993)
(Available for sale at Amazon.  
Click here.)

The 756th Tank Battalion in the European Theater
edited by Cheryl Esposito
(1999)
(
Currently out of print)

Books where the 756th Tank Battalion is mentioned prominently:

The History of the Third Infantry Division in World War II
edited by Donald G. Taggart
(1946) The Battery Press, Nashville Tennessee
(Reprints available through The Battery Press.  
Click here)

The Story of the Famous 34th Infantry Division  
by Lt. Col. John H. Hougen
(1949) The Battery Press, Nashville Tennessee
(Reprints available through The Battery Press.  
Click here)

Other books that mention the 756th Tank Battalion:

Cassino 1944: Breaking the Gustav Line
by Ken Ford
(2004) Osprey Publishing

Salerno to Cassino
by Martin Blumenson
(1969) Center of Military History

Cassino to the Alps
by Ernest F. Fisher, Jr.
(1977) Center of Military History

Riviera to the Rhine
by Jeffrey J. Clarke and Robert Ross Smith
(1993) Center of Military History

Report of Operations: the Seventh United States Army in France and Germany
1944-1945 (Two Volumes)
The Battery Press, Nashville Tennessee

The Second D-Day
by Jacques Robichon
(1962) Walker and Company, New York

Steel Victory: The Heroic Story of America's Independent Tank Battalions at War in
Europe
by Harry Yeide
(2003) Presidio Press, Ballantine Books, New York.

Tank Battalions of the U.S. Army
by James A. Sawicki
(1983) Wyvern Publications; Dumfries, Virginia.