TM 9 - 2300 - 216 - 10: full tracked, 175 mm., M107 (T235E1) (2350 - 436 - 6635) and Howitzer, heavy, self-propelled : full tracked, 8 inch, M110 (T236E1) (2350 - 436 - 6243).
UNITED STATES. War office. Headquarters department of army | US Government Printing Office | 1962