Hierarchies of Function Classes Defined by the First-Value Operator: (Extended Abstract).

Armin Hemmerling Hierarchies of Function Classes Defined by the First-Value Operator: (Extended Abstract). 59-72 2005 120 Electr. Notes Theor. Comput. Sci. http://dx.doi.org/10.1016/j.entcs.2004.06.034 db/journals/entcs/entcs120.html#Hemmerling05