CQ Researcher is an unusual source because it's sort of both a database and a journal at the same time. So the best citation format you should use is for a journal article, and the name of the journal is CQ Researcher.
Here is an example of a citation from CQ Researcher done in MLA, 8th edition style:
Hosansky, David. "Traffic Congestion." CQ Researcher, 26 Jan. 2018, pp. 73-96, library.cqpress.com/cqresearcher/cqresrre2018012600.
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