パンジャーブ語
Bhatia, T. "Punjabi: A Cognitive-Descriptive Grammar", 1993. p 279. ISBN 0-415-00320-2
The Times of India - "Punjabi, Urdu made official languages in Delhi" 25 June 2003
Canadian Census Data (2001)
Advanced Centre for Technical Development of Punjabi Language, Literature and Culture
Masica, CP, "The Indo-Aryan Languages", ISBN 0-521-29944-6, p 20