1. L. J. Richter, “Degrees of structures,” J. Symb. Log., 46, No. 4, 723-731 (1981).
2. J. F. Knight, “Degrees coded in jumps of orderings,” J. Symb. Log., 51, No. 4, 1034-1042 (1986).
3. E. B. Fokina, V. Harizanov, and A. Melnikov, “Computable model theory,” in Turing’s Legacy: Developments from Turing’s Ideas in Logic, Lect. Notes Log., 42, R. Downey (ed.), Cambridge Univ. Press, Ass. Symb. Log., Cambridge (2014), pp. 124-194.
4. I. N. Soskov, “Degree spectra and co-spectra of structures,” God. Sofij. Univ., Fak. Mat. Inform., 96, 45-68 (2004).
5. T. Slaman, “Relative to any nonrecursive,” Proc. Am. Math. Soc., 126, No. 7, 2117-2122 (1998).