D. G. Lewis, N. Lewis, editors (2005–present), “bywyn”, inGweiadur: the Welsh-English Dictionary, Gwerin
Delyth Prys, J.P.M. Jones, Owain Davies, Gruffudd Prys (2006)Y Termiadur: termau wedi'u safoni; standardised terminology[1] (in Welsh), Cardiff: Awdurdod cymwysterau, cwricwlwm ac asesu Cymru (Qualifications curriculum & assessment authority for Wales),→ISBN
R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “bywyn”, inGeiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies