APA
Roberts and associates, . (1998). Tertiary distance learning in sub-saharan africa: overview and directory to programs. washington, d.c: ADEA.
Chicago
Roberts and associates, . 1998. Tertiary distance learning in sub-saharan africa: overview and directory to programs. washington, d.c: ADEA.
Harvard
Roberts and associates, . (1998). Tertiary distance learning in sub-saharan africa: overview and directory to programs. washington, d.c: ADEA.
MLA
Roberts and associates, . Tertiary distance learning in sub-saharan africa: overview and directory to programs. washington, d.c: ADEA. 1998.