1. Stefan Heinrich's density condition for Fréchet spaces and the characterization of distinguished Köthe echelon spaces;Bierstedt;Math. Nachr.,1988
2. A question of Valdivia on quasi-normable Fréchet spaces;Bonet;Canad. Math. Bull.,1991
3. Sur les espaces (F) et (DF);Grothendieck;Summa Brasil. Math.,1954
4. J. Horváth Topological Vector Spaces and Distributions I (Addison-Wesley Publishing Co., Reading - Massachussets - Palo Alto - London, 1966).
5. Bases and reflexivity of Banach spaces;James;Ann. Math.,1950