Johnston, Trevor, author
Cambridge University Press, 2014
Buku Teks
edited by Anne E. Baker and Kees Hengeveld
Wiley-Blackweell, 2012
Buku Teks
edited by Archibald A. Hill
Voice of America, 1969
Buku Teks
edited by Archibald A. Hill
[Publisher not identified], 1969
Buku Teks
edited by Istvan Batori, Winfried Lenders, Wolfgang Putschke
Walter de Gruyter, 1989
Buku Referensi