Sources:

Bullock, H.A., Goldsmith, C.S., Zaki, S.R., Martines, R.B., and Miller, S.E. 2021. Difficulties in Differentiating Coronaviruses from Subcellular Structures in Human Tissues by Electron Microscopy. Emerging Infectious Diseases 27, 4, 1023–1031.
https://wwwnc.cdc.gov/eid/article/27/4/20-4337_article
DOI 10.3201/eid2704.204337

Jung, H., Kim, J.K., Lee, S., et al. 2014. Comparison of Filtration Efficiency and Pressure Drop in Anti-Yellow Sand Masks, Quarantine Masks, Medical Masks, General Masks, and Handkerchiefs. Aerosol and Air Quality Research 14, 3, 991–1002.
https://pdfs.semanticscholar.org/f215/d2555255314e9afe44b0e47a33e318775e81.pdfI
DOI: 10.4209/aaqr.2013.06.0201

Kim, M.-C., Bae, S., Kim, J.Y., et al. 2020. Effectiveness of surgical, KF94, and N95 respirator masks in blocking SARS-CoV-2: a controlled comparison in 7 patients. Infectious Diseases 52, 12, 908–912.
https://www.tandfonline.com/doi/pdf/10.1080/23744235.2020.1810858?needAccess=true
DOI: 10.1080/23744235.2020.1810858

Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C., et al. 2020. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine 26, 5, 676–680.
https://www.nature.com/articles/s41591-020-0843-2.pdf
DOI:10.1038/s41591-020-0843-2

BARONE, J.E., SOHN, N., and NEALON, T.F., JR. 1976. Annals of Surgery 184, 5, 601–604.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345490/pdf/annsurg00273-0077.pdf
DOI: 10.1097/00000658-197611000-00011

Aaron Collins on Youtube: https://www.youtube.com/channel/UC3fF_rzkmZD0ufN685YE7lg
Aaron Collins Test Data: https://docs.google.com/spreadsheets/d/1M0mdNLpTWEGcluK6hh5LjjcFixwmOG853Ff45d3O-L0/edit#gid=1976839763