Dearborn, Henry. Revolutionary War Journals of Henry Dearborn 1775-1783. Edited by Lloyd A. Brown and Howard H. Peckham. Chicago: The Caxton Club, 1939.
A New Hampshire officer, Dearborn participated in many campaigns including Saratoga. His journal concise and matter of fact, but a good overview source for dates and events.
Pausch, Georg. Journal of Captain Pausch – Chief of the Hanau Artillery during the Burgoyne Campaign. Edited by William L. Stone. Albany: Joel Munsell, 1886.
Oft neglected, Hessian diaries are good primary sources. While Pausch, provides more details on the events, leading up to the Saratoga campaign, he provides an eyewitness account of what it was like to be an officer on the Burgoyne invasion.
Rankin, Hugh F., ed. Narratives of the American Revolution – As Told by a Young Sailor, a Homesick Surgeon, a French Volunteer, and a German General’s Wife. The Lakeside Classics 75. Chicago: R. R. Donnelley & Sons Company, 1976.
Contained in this volume is the diary of Baroness von Riedesel, wife of the commander of German forces under General Burgoyne. Her accounts of tending to the wounded and her family under the guns of Patriot forces is heroic, poignant and riviting.
Brandow, John Henry. The Story of Old Saratoga and History of Schuylerville. Saratoga Springs, NY: Robson & Adee, 1906.
Elting, John Robert. The Battles of Saratoga. Philip Freneau Bicentennial Series on the American Revolution. Monmouth Beach, N.J: Philip Freneau Press, 1977.
Ketchum, Richard M. Saratoga: Turning Point of America’s Revolutionary War. New York: Holt paperbacks, 1999.
Luzader, John F. Saratoga: A Military History of the Decisive Campaign of the American Revolution. First paperback edition. New York: Savas Beatie, 2010.
Mintz, Max M. The Generals of Saratoga: John Burgoyne & Horatio Gates. New Haven: Yale University Press, 1990.
Nickerson, Hoffman. The Turning Point of The Revolution or Burgoyne in America. Boston and New York: Houghton Mifflin Company, 1928.
Snow, Dean R. 1777: Tipping Point at Saratoga. New York, NY: Oxford University Press, 2016.
The Saratoga town historican operates a web site devoted to the history of the battle and the surrounding area. It is a valuable resource for finding both primary sources as well as interesting facts and events.