http://www.businessdictionary.com/definition/primary-research.html
https://whatis.techtarget.com/definition/survey-research
https://www.snapsurveys.com/blog/advantages-disadvantages-surveys/
https://www.questionpro.com/blog/primary-research/
https://www.questionpro.com/blog/secondary-research/
https://vittana.org/23-advantages-and-disadvantages-of-qualitative-research
https://thinkturquoise.com/blog/market-research/10-key-benefits-of-market-research/
https://vittana.org/23-advantages-and-disadvantages-of-qualitative-research
https://keydifferences.com/difference-between-primary-and-secondary-research.html
https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100451291
https://www.the-numbers.com/movie/DUFF-The#tab=box-office
https://www.imdb.com/title/tt1666801/reviews