ISBNs beginnend mit 978-3-604-xxxxx-xO'Keefe J J × People OverheardStudent's BookO'Keefe J JHeuberger Verlag 1979 People OverheardStudent's Listening TextsO'Keefe J JHeuberger Verlag People OverheardTeacher's BookO'Keefe J JHeuberger Verlag 1979