I had not seen that paper; it is interesting and I will look over it more fully at another time. I should note that

• They aren't measuring work, they are measuring leisure. For example, they count the big increase in time spent in education as eating into our leisure, which is true, but irrelevant to the question of whether we are working more.
• Even those authors agree that per capita leisure increased by 4 hours per week over the past century in the USA.
• Some of their claims are hard to believe. For example, they claim

Home-production time averaged over the population ages 14 and older decreased by only half an hour per week from 1900 to 2005.

Really? Despite the gas oven, the washing machine, the dishwasher, etc? They claim that the typical 25-54-aged woman worked 50.4 hours per week in home production in 1900, and 31.1 hours per week in 2005. This change is way too small to be plausible. I think, frankly, that all kinds of activities are now being classified as home production work that would not have been so classified in 1990, and that their broad categories ("childcare", etc) are unable to measure this.

You can see a general overview of the subject for the US here:

http://eh.net/encyclopedia/hours-of-work-in-u-s-history/

A nice blogger put together a graph over hours worked over time in US history here:

http://1.bp.blogspot.com/_9kFluQyx4tM/TIcLhFVzVNI/AAAAAAAAAG8/hwfkDvU14-Y/s1600/Avg+Hours+Week.jpg

Data from various developed countries here:

http://phe.rockefeller.edu/work_less/