Helminen, Marjaana
Wolters Kluwer, 2010
Buku Teks
Paddeu, Federica, 1982-
Cambridge University Press, 2018
Buku Teks
Fenwick, Charles G.
Appleton-Century-Crofts, 1948
Buku Teks
Shaw, Malcolm Nathan, 1947-
Cambridge, 2003
Buku Teks
Wallace, Rebecca M. M.
Sweet & Maxwell, 2013
Buku Teks