It's a shame that this paper uses a URL shortening service intermediary for its links. Eventually, those links will become useless at discretion of that service and you can't even use them in the WaybackMachine either when that happens. Not only because those URLs are unremarkable on their own (I doubt the bitly links are present elsewhere on the web so the WaybackMachine would be triggered into archiving them), but also because I doubt the WaybackMachine would scan PDFs for links.
I leave record of the URL redirections here:
-> https://www.theguardian.com/technology/2019/jul/22/google-pa...
-> https://www.psychologytoday.com/us/blog/boomers-30/201710/yo...
-> https://www.quora.com/Is-30-years-old-too-old-to-learn-compu...
-> https://www.un.org/en/sections/issues-depth/ageing/
-> https://empirical-software.engineering/assets/data/google-se...
-> https://github.com/sbaltes/api-retriever
-> https://www1.eeoc.gov/laws/types/age.cfm
-> https://www.eeoc.gov/laws/types/age.cfm
-> http://www.eeoc.gov/age-discrimination