Use the Library search tool to find scholarly sources that are both directly about journalism and events/topics that are covered by journalists.
Since you only need one scholarly source, try for one that is specifically focused on ethics.
A couple of searches that worked well for me:
journalism ethic* (the asterisk at the end will prompt Library Search to look for either ethics or ethical)
photojournalism ethic*
You could then try narrowing the search down closer to your topic by adding another word or word.
journalism ethic* war
journalism ethic* celebrity
journalism ethic* race (or racism)
You could also use news or "news media" to replace journalism, which will change up the results or for photojournalism try news images or news photographs.
