MIT OpenCourseWare, 2.080J Structural Mechanics, Fall2013, Lecture3. The official lecture index identifies Tomasz Wierzbicki as instructor: ocw.mit.edu/courses/2-080j-structural-mechanics-fall-2013/pages/lecture-notes/ . Sections3.4–3.5, equations3.46 and3.52–3.57, printedpp.3-18–3-20, derive beam virtual work, endpoint moment/rotation pairs and alternatives between prescribed end loads and prescribed end motions.