the work of Friedman (1957) and Modigliani and Brumberg (1954) on consumption, Eisner and Strotz (1963) and Jorgenson (1963) on investment in physical capital, Becker (1962) and Ben Porath (1967) on investment in human capital, Baumol (1952), Tobin (1956), Meitzer (1963), and Brunner and Meltzer (1963) on money demand, all contributed.