Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
A History of the Development of Mine Ventilation (booklet)
A lecture by L. Irwin read at the Belfast Association of Engineers meeting, 9 February 1955. 19 pages.
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.