Marion, C., Vause, T., Harapiak, S., Martin, G. L., Yu, C. T., Sakko, G., & Walters, K. L. (2003). The hierarchical relationship between several visual and auditory discriminations and three verbal operants among individuals with developmental disabilities.

Marion, Carole, Tricia Vause, Shayla Harapiak, Garry L. Martin, C. T. Yu, Gina Sakko, i Kerri L. Walters. The Hierarchical Relationship between Several Visual and Auditory Discriminations and Three Verbal Operants Among Individuals With Developmental Disabilities. 2003.

Marion, Carole, et al. The Hierarchical Relationship between Several Visual and Auditory Discriminations and Three Verbal Operants Among Individuals With Developmental Disabilities. 2003.