4 books
Gruson's Chilled Cast-Iron Armour (Classic Reprint)
The Shielded Mountings on the Trial Ranges of the Grusonwerk at Magdeburg-Buckau and Tangerhutte, Part 2... - Primary Source Edition
Gruson's Chilled Cast-Iron Armour
The Shielded Mountings on the Trial Ranges of the Grusonwerk at Magdeburg-Buckau and Tangerhutte, Part 2...