Here is a small selection of the Library writing and style guides. The Chicago Manual of Style, now in its 17th edition, is the preferred style used by historians. The Manual is available online for consultation.
Chicago Manual of Style OnlineThe online version includes a Citation Quick Guide as handy reference. Access to the 16th edition is also available.
Brundage, Anthony. Going to the Sources: A Guide to Historical Research and Writing. Fifth edition. Chichester, West Sussex, UK: Wiley Blackwell, 2013.
Mabbett, Ian W. Writing History Essays. 2nd edition. London: Macmillan Education/Palgrave, 2016.
Storey, William Kelleher. Writing History: A Guide for Students. 4th ed. New York: Oxford University Press, 2013.
Cullen, Jim. Essaying the Past: How to Read, Write, and Think About History. 2nd ed. Chichester, West Sussex ; Malden, MA: Wiley-Blackwell, 2013.