What Makes a Problem GP-Hard? Analysis of a Tunably Difficult Problem in Genetic Programming. - Jason M. Daida; John Polito; Steven A. Stanhope; Robert R. Bertram; Jonathan C. Khoo; Shahbaz A. Chaudhary (GECCO, 1999)

What Makes a Problem GP-Hard? Analysis of a Tunably Difficult Problem in Genetic Programming. - Jason M. Daida; Robert R. Bertram; Stephen A. Stanhope; Jonathan C. Khoo; Shahbaz A. Chaudhary; Omer A. Chaudhri; John Polito (Genet. Program. Evolvable Mach., 2001)