EUROPA PUBLICATIONS LTDA. (1997). The world of learning 1998 (ed.48.). Europa Publications limited.
Chicago-viite (17. p.)EUROPA PUBLICATIONS LTDA. The World of Learning 1998. ed.48. London: Europa Publications limited, 1997.
MLA-viite (9. p.)EUROPA PUBLICATIONS LTDA. The World of Learning 1998. ed.48. Europa Publications limited, 1997.