Integration by parts are key to solving aerodynamics problems (Navier-Stokes, Euler, potential equations of motion) and is widely used in aeroelasticity. The reader is encouraged to explore any paper that uses computational fluid dynamics and computational structural dynamics to see how these are used. For aerospace applications, the suite of American Institute of Aeronautics and Astronautics (AIAA) journalsand the Journal of the American Helicopter Society (JAHS)include a number of these papers.