How to get the exact figures of these different types of research papers? How many references should we use while preparing a review article? Is there any essential parameter defining good review.
1. Target a particular conference in your field. Search for "Call for papers".
2. (WIDE:) To find the emerging patterns, you need to load as many as possible _relevant_ papers into your Document Library (I recommend http://www.qiqqa.com/70557). Tag your PDF files. Rate them.
(DEEP:) In your review, drop 80% of the papers, and only give short individual reviews for the remaining 20%. State the emerging themes. Summarize overall what you find. Close by stating what needs to be done!
3. You need to do what nobody has thought of doing before, and which is useful. WIDE & DEEP!
@Kusum, the essential parameter for review papers is a new/distinct view on all the literature available on your review topic. What methods do the studies use, how are they organised, any common rubrics? Work out new overall insight.
There may be many papers to review or only 21, but be sure you cover all relevant sources. You don't want to get caught falling short of references, especially of the important ones (those that are cited).