Fantastic Set of Farm Scene Lithographs - Teacher's Aid

This is a rare find, I can find no equivalents of these lithographs on ebay or anywhere else - even on Google. This is entitled "A Trip to the farm" a set of 12 - unused - farm scenes, plus the teacher instruction sheets and original envelope they came in. From the estate of a local teacher these are from the 1960s I think. In extraordinary condition, very fine quality art work.