Plan and section of east branch of Great Drain; unfinished ... John Travlos ... Possibly section Λ? Dirty Cartridge Paper Drafting Ink
Plan of the Great Drain at fork in Section Ζ ... Charles S. Spector ... Dirty Cartridge Paper Drafting Ink ... 1933
Plan and elevation of the Great Drain in Section E ... Charles S. Spector ... Dirty Cartridge Paper Drafting Ink ... 1933
Working plans of section Ζ in 1954. Earlier periods ... John Travlos Dorothy Burr Thompson ... Original missing. Old grid. Not an accurate plan! Faint Diazotype Drafting Ink Pencil Pen ... 1954
