This style has two documentation systems (1) notes and bibliography and (2) author-date.The notes and bibliography style is preferred by many in the humanities, including those in literature, history, and the arts. The author-date system is most often used by those in the physical, natural, and social sciences.
This citation style is the one preferred by the School of Theology and Seattle Pacific Seminary. Its default is (1) notes and bibliography (6.1-4, pp. 68-104), but it offers also (2) an author-date and works cited option for "Authors writing in [practical theology and] the social sciences" (6.5, pp. 104-108). It is based on Chicago style. SBL stands for the Society of Biblical Literature.