Levinson, N. (1940). Gap and density theorems. American Mathematical Society.
Chicago-čujuhus (17. p.)Levinson, Norman. Gap and Density Theorems. New York: American Mathematical Society, 1940.
MLA-čujuhus (9. p.)Levinson, Norman. Gap and Density Theorems. American Mathematical Society, 1940.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.