Bergendal, Gunnar Convergence and summability of eigenfunction expansions connected with elliptic differential operators. (English) Zbl 0093.06901 Meddel. Lunds Univ. Mat. Sem. 15, 5-63 (1959). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 10 Documents Keywords:approximation and series expansion of real functions PDF BibTeX XML OpenURL