Which libraries are included in the Scopus citation database? Is there a list of libraries which are included in the Scopus database? 

I am working in the field of Human Computer Interaction and searching for a list of included libraries (e.g. ACM, AIS and so on).
I don't think Scopus manages their indexing by what you call "Libraries" (you probably mean publishers, and I agree that many publishers seem to call their online publishing platforms something like "digital library"). Instead, Scopus selects individual titles for indexing. That means that not all titles offered in a specific "library" may be contained in the database. Scopus offers a list of titles they are indexing on their website, which you could use to research the titles that you are interested in.