Medvedev Degrees of Generalized R.E. separating Classes.

Douglas Cenzer Peter G. Hinman Medvedev Degrees of Generalized R.E. separating Classes. 203-223 2007 167 Electr. Notes Theor. Comput. Sci. http://dx.doi.org/10.1016/j.entcs.2006.08.014 db/journals/entcs/entcs167.html#CenzerH07