Azarparand, S. (2007). Perushiago ni okeru keigo hyougen, Gengo shyakai, 2, Tokyo: Hitotsubashi University, 438-456.
Brown, P. and Levinson, S. (1987). Politeness: some universals in language usage. Cambridge university press.
Hodge, C. T. (1957). Some aspects of Persian style. Language, 33-3, 366-369.
Ibraheem, M. M. (1841). A grammar of the Persian language. East-India college fhalleybury, 160-176.
Jahangiri, N. (1980). Dissertation on “ A sociolinguistic study of Tehrani Persian ”, London university.
Kabata, H. (1999). Keigo hyougen, taishukan shoten.
Kikuchi, Y. (1994). Keigo, tunogawa shoten.
Kuroyanagi, T. (1989). Yasashi Perushiago bunpou, tairyusha, 118-120.
Lambton, A.K.S. (1953). Persian grammar. Cambridge university press, 166-171.
Hickey, L. and Stewart, M. (2005). Politeness in Europe, Cromwell Press Ltd.
Minami, F. (1977). Keigo no kinou to keigo koudou,Ono, S. & Shibata, T, ed. Nihongo, Keigo, Iwanami kouza, 4, Iwanami shoten, 1-29.
Modarresi Tehrani, Y. (1391/2012). Daramadi bar jamee shenasiye zaban, Tehran: Institute for Humanities & Cultural Studies.
Moinfar, J. (1978). Grammaire du Persan. publie’ aree le du centre national de la recherche scientifique, 117.
Phillott, D. C. (1919). Higher Persian grammar, Calcutta University press, 68-70.
Oishi, H. (1975). Keigo, Chikuma Shoten.
Ono, S. and shibata, T. ed. (1977). Nihongo, Keigo. Iwanami koza, Vol.4. Iwanami shoten.
Rosen, F. (1979). Persian grammar. New Delhi, 286-288.
Suzuki, K. and Kobayashi, ed. (1984). Kenkyu shiryo nihongo bunpou, keigohou hen, 9, Meiji shoin.
Tanaka, H, ed. (1997). Gendai gengogaku jiten, Seibidou, 765.
Tsujimura, H. (1977). Nihongo no keigo no kouzou to tokushoku, In Ono, S. & Shibata, T, ed. Nihongo, Keigo, Iwanami kouza, 4, Iwanami shoten, 46-83.