Missouri Historical Review (October 2014, v. 109, n. 1) - What Men Expected, What Women Did: The Political Economy of Suffrage in St. Louis, 1920-1928 by Linda Harris Dobkin, pp. 1-17 (request through interlibrary loan)
Google often links to results in Newspaper.com. This resource is not free and subscriptions are not available through libraries. However, the Google results page will tell you what newspaper your hit came from. You can take that information to a free newspaper database or sign-up for the Newspapers.com 7-day free trial.
This is a collection of nationwide digitized newspapers. These will be especially helpful if you find your suffragist moved out of Missouri. This is also a good place to start your research if you have no luck searching the Missouri newspapers.
If your suffragist has a WW14 next to her name, a short biography will be available in this publication. HINT: search google by woman's name and click the Woman's Who's Who of America link.
An essential collection of genealogical and historical sources including primary sources and local and family histories with coverage dating back to the 1700s.