“SOME RESULTS ON THE UPPER-SEMILATTICE OF R.E. $m$-DEGREES INSIDE A SINGLE R.E. $tt$-DEGREE”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 96, pp. 23–34, Dec. 2004, Accessed: Jan. 11, 2026. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/158