These library databases are the most useful for historical research:
Tip--When searching Google for websites:
Still need to determine if a website you found is reliable? The CRAAPP Test will ask all the right questions to determine the reliability and usefulness of a site.
Start with the Basics:
This is a commercial site that will simply inform you about the basic information of the film: date, actors, directors, basic plot, etc.
This is a publicly editable encyclopedia which can have similar information as IMDb, plus, if the page is well done, will contain links to sources in the References section.