North Thames Gas Board. Romford undertaking. General recommendations for the operation and maintenance of catalytic oil gas plant heavy oil working / Humphreys & Glasgow Limited. [Comprises sections I-VI (38p. ts.), and references to 83 drawings and charts (c.77 present) and a further 42 drawings not present. Front board bears title 'North Thames Gas Board. Romford - A. Operating and maintenance instructions for Humphreys-Glasgow ONIA-GEGI catalytic oil gas plant']