Strand, P., Friman, P., Smeets, P. M., Holmes, D. B., & Holmes, Y. B. (2004). Establishing relational responding in accordance with more-than and less-than as generalized operant behavior in young children. International Journal of Psychology and Psychological Therapy.

Strand, Paul, Patrick Friman, Paul M. Smeets, Dermot Barnes Holmes, and Yvonne Barnes Holmes. "Establishing Relational Responding in Accordance With More-than and Less-than as Generalized Operant Behavior in Young Children." International Journal of Psychology and Psychological Therapy 2004.

Strand, Paul, et al. "Establishing Relational Responding in Accordance With More-than and Less-than as Generalized Operant Behavior in Young Children." International Journal of Psychology and Psychological Therapy 2004.