How are the research fields CSCW and HCI related historically?

As part of writing my thesis, I was trying to reconstruct how exactly the research field of Computer-Supported Cooperative Work (CSCW) is related to Human-Computer Interaction (HCI).

I have a decent understanding of the differences and overlap between the two, but was wondering to which degree they overlap historically. I presumed CSCW to have split off from HCI as a wider subject area since the field seemingly predates it, but have found no evidence in this regard. For example, the wikipedia page on CSCW does not even mention HCI, whereas that of HCI merely mentions the overlap of which I am already aware.

A quick search (search for 'HCI') in a recent overview of CSCW by Schmidt and Bannon (2013) does not even seem to mention a historical link between HCI and CSCW.

How exactly are the two related historically?

_{Schmidt, K., & Bannon, L. (2013). Constructing CSCW: The first quarter century. Computer Supported Cooperative Work (CSCW), 22(4-6), 345-372.}