I will access the internet databases and search engines in order to find links to sources. Old magazines, anthologies, or retrospectives might be helpful in gathering information. The American Movie Classics magazine, for instance would be a good place to look. Interviews may be possible with antique retailers or memorabilia shop owners. The American Movie Classics channel frequently runs specials about classic Hollywood subjects.
Entertainment offers interviews with the stars as well as clips from musicals from that time period.
Another possible source might be biographies of important people of that era, like studio executives and major stars. I will organize the information into categories based on the main subjects to be analyzed in my research paper.