http://www.payscale.com/career-news/2013/03/the-5-worst-jobs-in-history-were-way-worse-than-yours
http://www.jobsite.co.uk/worklife/10-worst-jobs-history-11553/
http://brainz.org/16-worst-jobs-through-history/
http://www.broadsheet.ie/2013/06/14/13-of-the-worst-jobs-in-history/
http://listverse.com/2009/09/24/top-10-strangest-jobs-in-history/