I am looking for peer reviewed/scholarly articles on the topic "gangs in the military" or "Houston gangs".
On the first topic, gangs in the military, I recommend starting at the library guide for Criminal Justice found here: http://library.uhd.edu/cj. This is a collection of key resources in criminal justice topics. From the multidisciplinary databases box click on LibSearch. This allows you to search a combination of databases at once as well as Academic Search Complete, a good general database. In the first box, type gangs, and in the second type military. To limit your results to peer reviewed journals, look in the center of the page under the Limit you Results heading. on the right, check the box for "Scholarly (Peer Reviewed) Journals". This will limit your results to the kind of resources you are looking for.
On the second topic, Houston gangs, I recommend you visit the website of the City of Houston Anti-Gang Office (http://www.houstontx.gov/antigang/). Also, Houston has a joint effort to stop gangs – you can find the Web site at http://stophoustongangs.org/. One of the participants is the Harris County Sheriff’s Office; their Web site is http://www.hcso.hctx.net/. They have a tool called Crime Reports on their front page that seems to allow you to define a neighborhood and get statistics on crime. You may also want to look over the library's Criminal Justice Research Guide http://library.uhd.edu/cj. From this guide, if you click on the tab for Websites and Statistics, there are several link to local and regional crime resources.
For Peer Reviewed articles on this topic, it may be difficult to find information specific to Houston. Try the same method suggested for the "Gangs in the Military" topic. If you are not finding the information you are looking for, try broadening your search by looking for Gangs and Cities. When you are looking at your results pages, check out the column on the left side of the page. Under the Subject headings, you can looks for other subjects related to your topic. This may help you come up with additional/different search terms.