“…A detailed description is provided of the contingency analytic foundations of HRC by Layng, Sota, & Leon (2011), of the analysis that determined its content by Sota, Leon, and Layng (2011), and of the programming and testing of the repertoires and relations involved by Leon, Layng, & Sota (2011). The methods Headsprout employs in the design, development, and testing of all its programs has been described by Layng, Twyman, & Stikeleather (2003), Twyman et al (2004), and Layng, Stikeleather, and Twyman (2006).…”