Sekolah Tinggi Agama Islam Negeri (STAIN) Tulungagung,
Majalah, Jurnal, Buletin
Ross, Alf
Longmans, Green , 1947
Buku Teks SO
Fawcett, Joe
John Wiley & Sons, 2012
Buku Teks SO
by Tomas Tomascik ... [and others]
Periplus Editions, 1997
Buku Teks
Jones, Alan J.
Departement of Industry Technology and Commerce, 1990
Buku Teks SO