  In this paper, we answer a set of research questions that are required to
develop service identification approach based on the analysis of object-
oriented software. Such research questions are: (1) what is a service, (2) how
are services different from software components, (3) what are types of
services, (4) what are existing service identification approaches that consider
service types into account, and (5) how to identify services based on the
object-oriented source code with respect to their types. Our methodology is
based on performing a literature review to identify the answers of these
research questions. Also, we propose a taxonomy of service types.
