For example: http://www.danzpage.com/Construction-Management-Resources/Ca...
(Hourly productivity is lower during the 60 hour weeks, but weekly product is higher.)
I have never seen a result that says no one can work 60+ hours regularly. I've never seen a result that even applied to knowledge workers - the entire literature is about construction and manufacturing.
So if you want to make a strong claim that "100+ years of research" proves something, please cite the research. If it's so voluminous, it shouldn't be hard.
(Incidentally, just remembered Claudia Goldin's paper on gender gaps. She cites a bunch of literature showing that in some occupations, productivity is actually superlinear in the number of hours worked, not sublinear like construction. http://www.aeaweb.org/aea/2014conference/program/retrieve.ph... )