1. Martin's Axiom does not imply that every two N1-dense sets of reals are isomorphic;ABRAHAM;Israel J. Math.,1981
2. On the consistency of some partition theorems for continuous colorings, and the structure of N-dense real order types;ABRAHAM;Ann. Pure Appl. Logic,1981
3. N1-trees;DEVLIN;Annals Math. Logic,1978
4. A. HAJNAL and I. JUHÁSZ [1975] On first-countable non-Lindelöf spaces, Proc. of the “Infinite and Finite Sets” Coll. 1973 (North-Holland, Amsterdam) 837–852.