results about free distributive lattices. I have corresponded with 2012 Nobel laureate in Economics Al Roth, who introduced me to students of his. Al Roth's first paper, as far as I can tell, was in my field, lattice theory. http://www.ams.org/journals/bul1/1975-81-01/S0002-9904-1975-13672-X/S0002-9904-1