Bhai Bula, mentioned by Bhai Gurdas, Varan, XI. 15, as one of the devoted Sikhs of the time of Guru Angad.
1. Mani Singh, Bhai, Sikhan di Bhagat Mala. Amritsar, 1955
2. Gian Singh, Giani, Twarikh Guru Khalsa. Patiala, 1970
3. Santokh Singh, Bhai, Sri Gur Pratap Suraj Granth. Amritsar, 1926-37