Updated 4/3/2020
Designs:
https://www.nytimes.com/2020/03/31/well/live/coronavirus-N95-mask-DIY-face-mask-health.html
https://fortune.com/2020/03/29/coronavirus-face-mask-shortage-new-design-covid-19/
https://maidsailors.com/blog/how-to-make-a-surgical-mask/
https://www.instructables.com/id/Homemade-Micro-particle-Face-Mask/
https://smartairfilters.com/en/blog/best-materials-make-diy-face-mask-virus/
http://tinyurl.com/safetymasks
https://www.youtube.com/watch?v=p4USPU1Trz4
https://docs.google.com/document/d/1J1URA4bYiHYEUHL7lTprM1aYuFwdzm0Df9aOuQTBlSo/edit
Interesting:
https://thewirecutter.com/blog/homemade-face-masks-coronavirus/
https://bmjopen.bmj.com/content/5/4/e006577