^Grewal, Dalvinder Singh (2011). "Chanting 'Waheguru' is Pure Bliss!".The Sikh Review.59 (691–696). Calcutta, India: Sikh Cultural Centre: 9.
^Singh, Pashaura; Fenech, Louis E., eds. (2014). "The Khalsa: Foundational Myth of the Sikh 'Nation'".The Oxford Handbook of Sikh Studies. Oxford Handbooks in Religion and Theology. Oxford: Oxford University Press. p. 272.ISBN978-0-19-969930-8.OCLC874522334.Nanak conceived of God as the one and the only 'true sovereign' (Sacha Patishah) of the world; although the term Vahiguru first found in the hymns of Bhatt Gayand, the bard contemporary of Guru Arjan (the fifth Guru), is now more commonplace and used in the Sikh salutation (Vahiguru ji ka Khalsa Vahiguru ji ki Fateh).
^"Journal of Religious Studies".Journal of Religious Studies.36. Punjabi University. Department of Religious Studies: 46.Gayand composed 13 swayyas in praise of the fourth Guru whom he believes to be incarnate of the Divine. His 'Wah - Wah' phrase is popularly recited by the Sikhs
