Your search for "All money is a matter of belief. - Adam Smith 1723 - 1790" revealed the following:

YT-2.4- An investment in knowledge pays the best interest. - Benjamin Franklin 1706 - 1790

RW-2.4 - An investment in knowledge pays the best interest. - Benjamin Franklin 1706 - 1790

PWK-2.4-An investment in knowledge pays the best interest. - Benjamin Franklin 1706 - 1790