Andreas Abel Klaus Aehlig Peter Dybjer Normalization by Evaluation for Martin-Löf Type Theory with One Universe. 17-39 2007 173 Electr. Notes Theor. Comput. Sci. http://dx.doi.org/10.1016/j.entcs.2007.02.025 db/journals/entcs/entcs173.html#AbelAD07