Serrats, Marta
Page one publishing pte ltd, 2011
Buku Referensi
Rayfield, Julie K.
John Wiley & Sons, 1994
Buku Teks
Serrats, Marta
LOFT Publications S.L., 2011
Buku Teks
Nussbaumer, Linda L.
Fairchild Books, 2009
Buku Teks
Kurtich, John
Van Nostrand Reinhold, 1993
Buku Referensi