An Efficient Student Model Based on Student Performance and Metadata. - Arndt Faulhaber; Erica Melis (ECAI, 2008)

Interoperable Competencies Characterizing Learning Objects in Mathematics. - Erica Melis; Arndt Faulhaber; Anja Eichelmann; Susanne Narciss (Intelligent Tutoring Systems, 2008)

Supporting Flexible Competency Frameworks. - Erica Melis; Arndt Faulhaber; Ahmad Salim Doost; Carsten Ullrich (ICWL, 2010)