Its scanned from the book:
The Avro Lancaster
A Comprehensive Guide for the Modeler
Lincoln and Manchestor
By Richard A. Franks
ISBN: 0-9533465-3-6
SAM Publications
As the title suggests its a book for modelers and contains many 3 view line drawings, cockpit layouts illustrations and photos, crew positions etc.
There is also a complete list of all Lancasters (foreign and civilian versions), Lincolns and Manchesters built. As well as squadron listings, variant tech info etc...
As well as:
There's also line drawings of the various bombs.