Full context:   Other researchers developed similar systems, many of which did not use the ancient temperament names, and several paired extraversion with a different factor which would determine relationship and task-orientation. Examples are DISC assessment and social styles. One of the most popular today is the Keirsey Temperament Sorter, attributed to the work of David Keirsey, whose four temperaments were based largely on the Greek gods Apollo, Dionysus, Epimetheus, and Prometheus, and were mapped to the 16 types of the Myers–Briggs Type Indicator (MBTI). They were renamed as Artisan (SP), Guardian (SJ), Idealist (NF), and Rational (NT). C.G. Jung's Psychological Types surveys the historical literature of the 'four humors' and related discussions extensively and in depth and proposes a psychoanalytic integration of the material.