Characterization of subspaces and quotients of nuclear L f ( α , ∞ ) -spaces Heikki Apiola — 1983 Compositio Mathematica
Duality between Spaces of p-Summable Sequences (p, g)-Summing Operators and Characterizations of Nuclearity. Heikki Apiola — 1976 Mathematische Annalen
Some permanence properties of locally convex spaces defined by norm space ideals of operators Heikki Apiola — 1976 Studia Mathematica