1. A. Arhangel’skii, The frequency spectrum of a topological space and the product operation, Trans. Moscow Math. Soc. 2 (1981), 163–200.
2. Internal characterizations of productively Lindelöf spaces;Aurichi, Leandro F.;Proc. Amer. Math. Soc.,2018
3. Cambridge Tracts in Mathematics;Fremlin, D. H.,1984
4. Cardinal functions. I;Hodel, R.,1984
5. Studies in Logic (London);Kunen, Kenneth,2011