Three theorems on closure of biorthogonal systems of functions
Author:
R. E. Langer
Journal:
Bull. Amer. Math. Soc. 33 (1927), 97-105
DOI:
https://doi.org/10.1090/S0002-9904-1927-04323-3
MathSciNet review:
1561327
Full-text PDF Free Access