^ Hassandoust, Mohammad (2002/2003–) “اَرْس”, in Bahman Sarkarati, editor, Farhang-e riše-šenâxti-ye zabân-e Farsi [An Etymological Dictionary of the Persian Language] (in Persian), Tehran: Academy of Persian Language and Literature, →ISBN, page 78
^ Gharib, B. (1995) “cškw”, in Sogdian dictionary: Sogdian–Persian–English, Tehran: Farhangan Publications, page 129
^ Gharib, B. (1995) “ʾckw”, in Sogdian dictionary: Sogdian–Persian–English, Tehran: Farhangan Publications, page 24