This citation guide from Indiana University lists citation formats based on which database you use. Use CTRL+F or CMD+F on your computer to navigate to the database you are using and need to cite.
What's Being Done?
Here are some good strategies to find out what solutions may already exist for the problem you identified:
Use the UC Libraries database Business Source Complete. Search for similar ideas ("fitness app") and then use the Trade Publications checkbox on the left-side of the search results to see latest news in the field
Use the Marketline database! Search for a company that does similar things to your idea and then look at the latest company news and recent deals the company negotiated.
Go to the main website of a related company and find their Press Releases, Company News, and/or Investor Relations page(s). Links to these are often found at the very bottom of the website's homepage.
Support Your Idea with Data
Now you need data to support your idea:
Use Marketline to search for a company that does similar things to your idea and then look at the SWOT analysis for the company to see their Strengths, Weaknesses, Opportunities, and Threats.
Marketline works best for companies listed in the NYSE (stock market). To find out if a company is on the stock
IBISWorld is a database with industry data. You can see the current state of an industry, the trajectory, and the industry SWOT. You can also see who major players in the industry are
Mintel has great (and recent) consumer survey data. You can explore the data online or click the Databook Excel button to download all the raw data to get demographic information on the survey answers (such as how did men over 45 years answer the question).
Sage Stats/Data Planet has a lot of in-depth survey and poll data. You can find data based on the topic or the source of data.
SimplyAnalytics allows you to look at survey data geographically. This could be great if you are targeting a particular region of the country or Ohio. You can also look at correlations between socioeconomic status and your data points on the map as well.