[https://www.foxbusiness.com/technology/elon-musk-got-4000-spacex-workers-to-join-a-covid-19-study-heres-what-he-learned](https://www.foxbusiness.com/technology/elon-musk-got-4000-spacex-workers-to-join-a-covid-19-study-heres-what-he-learned) "To monitor the prevalence of the virus among employees nationwide, the tech billionaire worked with researchers to build an antibody-testing program. Here’s what he learned."