Blakeney, E.H.
Everyman's smaller classical dictionary
J.M. Dent & Sons, 1952
 Buku Referensi
Schwartz, Robert J.
The complete dictionary of abbreviations
Crowell , 1955
 Buku Referensi
Jones, David J.
The Australian dictionary of acronyms & abbreviations
Australia, Second Back Row Press
 Buku Referensi
The oxford dictionary of abbreviations
Oxford University Press, 1996
 Buku Referensi
Jones, David J.
The Australian dictionary of acronyms & abbreviations
Second Back Row Press, 1981
 Buku Teks SO