Levinson, N. (1940). Gap and density theorems. American Mathematical Society.
Cita Chicago (17th ed.)Levinson, Norman. Gap and Density Theorems. New York: American Mathematical Society, 1940.
Cita MLA (9th ed.)Levinson, Norman. Gap and Density Theorems. American Mathematical Society, 1940.
Atenció: Aquestes cites poden no estar 100% correctes.