The Fortescue papers,
consisting chiefly of letters relating to state affairs, collected by John Packer, secretary to George Villiers, duke of Buckingham.
Edited, from the original mss ... by Samuel Rawson Gardiner.

APA Citation

Fortescue, G. Matthew., Gardiner, S. Rawson., Packer, J. (1965). The Fortescue papers: consisting chiefly of letters relating to state affairs, collected by John Packer, secretary to George Villiers, duke of Buckingham. New York: Johnson Reprint Corp.

MLA Citation

Fortescue, George Matthew, Hon., 1791-1877, Samuel Rawson Gardiner, and John Packer. The Fortescue Papers: Consisting Chiefly of Letters Relating to State Affairs, Collected by John Packer, Secretary to George Villiers, Duke of Buckingham. New York: Johnson Reprint Corp, 1965.

Warning: These citations may not always be complete (especially for serials).