Hierarchical Structures of Content Items in LMS. - Sharon Hardof-Jaffe; Arnon Hershkovitz; Ronit Azran; Rafi Nachmias (EDM, 2010)

Types of online hierarchical repository structures. - Arnon Hershkovitz; Ronit Azran; Sharon Hardof-Jaffe; Rafi Nachmias (Internet High. Educ., 2011)