Cocoon, Napping on the Boston Common

This is a rare lithograph by American artist Ture Bengtz.  The title is "Cocoon", it is the third state of three.  The subject is a man napping on a bench in the Boston Common.  The image is pencil signed lower border and numbered as 20.  The image measures 11X16 3/4 inches. The Boston statehouse in the  far distance.