Sometimes I find a particular concept which I can't find much description about in the books I know. Is it accepted to ask for references in such scenarios?
Yes, this is perfectly acceptable.
Of course, you should make sure that you follow the guidelines given in Are resource recommendations allowed?. To maximize the chances of success of your question:
- provide a description of the concepts that you're interested in with as much detail as you can
- provide a clear picture of what you do and don't understand, so that book recommendations can be given with the correct level of prerequisites
- make sure to look for existing resource-recommendation threads on similar subjects, and if they have a nontrivial overlap with your query, explain why they don't fit your needs