editor, Luigia Romano, Antonio Pinto
Springer, 2012
eBooks
edited by Francisco V. Cipolla-Ficarra
Igi Global, 2014
Buku Teks SO
Topping, J.
Chapman and Hall, 1972
Buku Teks SO
edited by Anthony D. Slonim
Wolters Kluwer, 2008
Buku Teks SO
Heaton, J.B.
Longman, 1987
Buku Referensi