There are many excellent search engines for publications:
Most of these sites allow to search for publications that cited a certain other citation. It is a good strategy to start with a few publications and find out whether there are better publications citing this.
In general a publication is considered to be the more reliable the more review it got. As a consequence there is roughly the following order (“>” meaning “is better than”, “~” meaning “as good as”):
|Journals > Conferences > Workshops > Technical Reports ~ Books > Online Presentations > Blogs ~ Newsgroups|
Favor the most recent papers over older papers, but look out whether there are classical papers. The Software Engineering discipline is getting a history these years, i.e. it becomes important how and when ideas arose and evolved.
If your topics happens to be shaped around products or processes and not primarily around a research question, you should look out for generic ideas in the material that you have and search for publications about these.
Most publications are available online if you connect to the webpages from within the university network.
You may find the following advice helpful: