Deontic logic, also referred to as the logic of obligation, is a relatively new branch of logic. The first attempt at constructing a formal system of deontic logic was made by Ernst Mally in 1926. Since then, several attempts followed, of which the most notable is that of G.H. von Wright in his classic paper "Deontic Logic", published in 1951. Von Wright's paper prompted a lot of reaction in the field and has influenced work in deontic logic ever since.
Azizah Y. al-Hibri, Deontic Logic: A Comprehensive Appraisal and a New Proposal (1978).