Muster Rolls, Company D, 21st Texas Infantry, Microfilm edition in Archives of the Nesbitt Memorial Library, Columbus and Richard V. Cook's letter of August 8, 1863, which is contained therein; Official Records, vol. 15, pp. 402-403, 1053. In November 1864, at his request, Cook's company was reassigned to the 13th Texas Infantry Regiment, where it was designated as Company A.