Find the package that fits your needs.  Purchase 15 research questions for as low as $6.25 per research question for the time period of 1900 to 1939.   Not all questions have to be asked at once, they can be spread out over a period of time, plus be billed monthly during the allocated time period.   Must be used in a 4 month period.  4 question limited per month, unless paid in full.   4 monthly payments of $23.45.