1. Novelty and functional equivalence in superordinate categorization by pigeons;Astley;Animal Learning & Behavior,1998
2. Superordinate category formation in pigeons: Association with a common delay or probability of food reinforcement makes perceptually dissimilar stimuli functionally equivalent;Astley;Journal of Experimental Psychology: Animal Behavior Processes,1999
3. Secondary generalization and categorization in pigeons;Bhatt;Journal of the Experimental Analysis of Behavior,1989
4. Conceptual behavior in pigeons: Categorization of both familiar and novel examples from four classes of natural and artificial stimuli;Bhatt;Journal of Experimental Psychology: Animal Behavior Processes,1988
5. Autoshaping of the pigeon's key-peck;Brown;Journal of the Experimental Analysis of Behavior,1968