Forty Year Men at Studebaker, 1951

Charles R. Foster.  Psychology for Life and Adjustment.  American Technical Society, 1951, 8th Printing 1959.

"Continued interest in their work" plus salaries plus benefits plus retirement plans.

From a very different era.  Four years after this book's 8th printing, the American Studebaker plant closed, although it lingered on a while longer in Canada.