Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
The Schaefer System (booklet)
'The Schaefer System of Supporting Underground Roads Tunnels Tubes and Shafts'. 24 pages, illustrated throughout. Undated.
Pwnc
Diwydiant
Rhif yr Eitem
2018.51/54
Mesuriadau
Meithder
(mm): 243
Lled
(mm): 157
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.