C. E. Bosworth;Vladimir Minorsky.«Wan». A: The Encyclopædia of Islam(en anglès). volum XI: W—Z. Leiden:Brill,2002,p.135.«Mustawfi's Nuzhat al-kulüb, 102, says that ‘Wan is a fortress while Wustan (Ostan) has been a large town but now is a medium-sized one’, and ‘Its climate and its fruits are good, its water comes from a mountain‘»