Citing summaries of many sources I am working on a "Handbook" on a technical topic I am personally interested in and I also need for work. To back up statements and provide reputable sources I try to cite everything even though it will never be published. Now I do not know how to cite this properly.

Example: I want to write about topic A. I have four books with multiple chapters that cover parts of topic A, as well as scripts from university, presentations and notes from seminars all around the same topic. Lots of them containing the same "premise" and common knowledge in the field. I now know quite a bit about this topic. I then write my own compact version of this topic A in my "Handbook".

How do I cite this? Normal "According to…" citing like in summaries does not work because every section is compiled of many sources. If I cite every source before or after every paragraph the thing becomes unreadable.

Is it acceptable to write something like: "Used in this chapter: Source1, Source2, etc." and when referencing to an specific statement or figure in a source using the full proper citation behind the statement or under the figure?

I have a book that does this. It just lists sources according to chapters in the back of the book: "Literature for chapter 1.8: Source1, Source2, Source3, etc." And cites only specific points in text.

I didn’t find a suitable example for this case in the citation guides I have and hope someone can help me out here. Thank you for your time.
I would recommend using a numeric citation style. Then you can say some like:

"Fooing the bar using the whats-it is regarded as producing the best results ([1]-[12])"

For even:

"Fooing bars has been addressed in many places ([1]-[5], [9], [102]-[125]), the following are common conclusions.... "