ISBN: 0521544629 (student's book)
ISBN: 0521544637 (self-study pack)
ISBN: 0521544645 (cassette set)
ISBN: 0521544653 (audio CD set)
ISBN: 9780521544627 (student's book)
ISBN: 9780521544634 (self-study pack)
ISBN: 9780521544641 (cassette set)
ISBN: 9780521544658 (audio CD set)