Benjamin B. Warfield — The Plan of Salvation: Five Lectures Delivered at the Princeton Summer School of Theology, June, 1914 (Philadelphia: Presbyterian Board of Publication, 1915).
Warfield sets out the possible answers to the question how God saves, as a series of choices, each narrowing the last: naturalism or supernaturalism (autosoterism against salvation from God), sacerdotalism or evangelicalism (the Church as the channel of grace, or God working immediately on the soul), universalism or particularism, and, within particularism, the order of the decrees — ending in Calvinism as evangelicalism consistently held.