I'm writing a paper in which I have reviewed a list of reports and have summarized data from each. I have cited each of those original reports. However, I originally located some of those reports because someone else wrote a similar paper years ago in which they listed sources (without summarizing), and I looked up the citations they had used. That is to say, they wrote a paragraph that said something along the lines of "This subject has been examined in the past by W, X, Y, Z" I am unclear on how to cite this secondary source. Do I write my summary, then cite both the original source and the secondary source, i.e.
Lorem ipsum dolor sit amet, curabitur voluptatum nullam sed placerat vestibulum (Original1 1960; Secondary 1990).
Lorem ipsum dolor sit amet, curabitur voluptatum nullam sed placerat vestibulum (Original2 1971; Secondary 1990).
This seems misleading, because I didn't actually draw the data from the secondary source, just used their list of citations. On the other hand, I really need to make reference to the fact that this secondary author created the list of sources that I used. Would it be better to make a statement that the second author listed the references, and just cite that paper once?