10.1184/R1/6609998.v1 Allen Newell Allen Newell Studies in problem solving ; subject 3 on the crypt-arithmetic task Donald + Gerald = Robert Carnegie Mellon University 1989 Problem solving. Human information processing. 1989-01-01 00:00:00 Journal contribution https://kilthub.cmu.edu/articles/journal_contribution/Studies_in_problem_solving_subject_3_on_the_crypt-arithmetic_task_Donald_Gerald_Robert/6609998 Computer Science Department