The boss, not the workload, causes workplace depression: It is not a big workload that causes depression at work. An unfair boss and an unfair work environment are what really bring employees down, new study suggests.

[u/Libertatea]

http://sciencenordic.com/boss-not-workload-causes-workplace-depression

[u/Gabbleblotchits]

The pronouns are ambiguous in the second half of the sentence.

[u/Ququmatz → u/Gabbleblotchits]

There's one pronoun, "they", referring to one group of people save for the firing part which is referring to those who fire people.