There are minor changes with the previous Project layouts guide 1974 document (layout dimensions added, change of the model of electric relay in page 12, corrections on layout component list in page 33)
There are several issues of this Project layouts guide 1975, which can identified on the bottom right corner of page 32, with different printings (GF 10-75, GF 11-76, G.F. 11/77, PRINTEX 80128 HEILLY 79, PRINTEX 80128 HEILLY 80)