High Quality Content by WIKIPEDIA articles! Paco Axel Lagerstrom (1914-1989) was an applied mathematician and aeronautical engineer. He was trained formally in mathematics, but worked for much of his career in aeronautical applications. He is known for pioneering work in applying the method of asymptotic expansion to fluid mechanics problems. Several of his works have become classics, including "Matched Asymptotic Expansions: Ideas And Techniques".