@inbook{Kuhlen,1963,
author = {Kuhlen, R.G.},
title = {Motivational changes during the adult years. },
booktitle = {Psychological Backgrounds for Adult Education},
editor = {Kuhlen, R.},
pages = {77-113},
year = {1963},
publisher = {Center for the Study of Liberal Education for Adul},
language = {English},
url = {eric.ed.gov/?id=ED027459}
}