Ralph Ince and Mitchell Leisen were both American what?
Mitchell Leisen Mitchell Leisen (October 6, 1898 – October 28, 1972) was an American director, art director, and costume designer.
Edward Lindsay Ince Prof Edward Lindsay Ince FRSE (1891–1941) was a British mathematician who worked on differential equations, especially those with period coefficients such as the Mathieu equation and the Lamé equation. He introduced the Ince equation, a generalization of the Mathieu equation.