Hello again, Altg20April2nd. With regard to using studies as old as you were using, I went over that at WP:MED; Wikipedia:Identifying reliable sources (medicine)#Use up-to-date evidence is clear that we should generally use the more recent studies when both the old and recent studies are available. There are exceptions mentioned there, but there is no valid reason to use a study as old as 1937, or other very old ones, unless we are using that in the context of explicitly stating how studies on this topic have varied over time; in other words, for historical information.