Bennett, Claire L., author
John Wiley & Sons, 1982
Buku Teks
Pollock, George, author
Springer, 2012
eBooks
Hawker, Jeremy, author
Wiley-Blackwell, 2012
Buku Teks
Ezekiel Kalipeni, Juliet Iwelunmor, Diana Grigsby-Toussaint, Imelda Moise, editors
Routledge, Taylor & Francis Group, 2018
Buku Teks
Webber, Roger, author
Cab International, 1996
Buku Teks