1. Structural properties of the degrees below 0′;Arslanov;Dokl. Akad. Nauk SSSR, N.S.,1985
2. Degrees of Unsolvability;Cooper,1971
3. The density of the low2 n-r.e. degrees;Cooper;Arch. Math. Logic,1991
4. The d.r.e. degrees are not dense;Cooper;Ann. Pure Appl. Logic,1991
5. Weak density and cupping in the d.r.e. degrees;Cooper;Israel J. Math.,1989