The Extensible Problem-Specific Tutor (xPST): Evaluation of an API for Tutoring on Existing Interfaces. - Stephen B. Gilbert; Stephen Blessing; Sateesh Kumar Kodavali (AIED, 2009)

Expansion of the xPST Framework to Enable Non-programmers to Create Intelligent Tutoring Systems in 3D Game Environments. - Sateesh Kumar Kodavali; Stephen B. Gilbert; Stephen Bruce Blessing (Intelligent Tutoring Systems (2), 2010)