Konkordienbuch
Additionally, the Association of Free Lutheran Congregations (AFLC) describes themselves as confessional. The autonomous congregations within the AFLC are only required to officially subscribe to the unaltered Augsburg Confession and Luther's Small Catechism, but many member congregations officially subscribe to more, or all, of the Book of Concord, while others do so unofficially in matters of doctrine and practice. All internally trained AFLC pastors are taught a "quia" subscription of the Book of Concord, leaving the denomination as a whole "unofficially" confessional in matters of preaching and teaching.