1. Specification for bevel protractors (mechanical and optical). (22nd May 1951) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (10 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
2. Specification for protractors for drawing office use. (31st January 1975) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (8 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗