This presentation concentrates on lines which use the word "duty" expressly, however, implications of "duty" are included where they are unmistakable. Subtle implications of duty may exist, and do, but are not included here. | This presentation concentrates on lines which use the word "duty" expressly, however, implications of "duty" are included where they are unmistakable. Subtle implications of duty may exist, and do, but are not included here. |