diff --git a/README.md b/README.md
index 268da5018342e1f306470e44e0a435c6d417020b..ae4558c06ef6f16b8a08d5995ce7a95d0647ff1a 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ so we're targeting filter material able to block particles with minimum ~0.25um
- challenge particles
- Bacillus atrophaeus : 0.95-1.25um, 10^7 cfu in challenge [^DIYmask]
- Bacteriophage MS2 MCIMB10108: single strange RNA ~20nm diameter, 10^9 pfu in challenge [^DIYmask]
- - E. Coli phi174 [^nelson]
+ - E. Coli phi174 [^VFEreport]
performance difference between pleated hydrophobic filters and electrostatic filters??
@@ -44,10 +44,16 @@ performance difference between pleated hydrophobic filters and electrostatic fil
[^collisonNebulizer]: [Collison Nebulizer](https://arxiv.org/pdf/2001.04498.pdf)
[^stability]: [Aeorsol and surface stability of HCoV-19 compared to SARS-CoV-1](https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v1.full.pdf?__cf_chl_jschl_tk__=e5c36168cc7402ab11178538c0ef5fdd2b8c8cbd-1584464414-0-AfohFaEsIDDjmqQ6YEGAmPrX14_fYwDCairndak5B58MzTDypSP7pDWh1jiStM9Xr_70C8k2y_R4fLiH9CFS5W4Y8Q3u3jMABGFCptEt34BXergTOg1G120143eK6Wib1g34BQflq9yKQ5kuuKjU7or6pxdvmtOIsI45onaedQTa8Ioxpo-tMjo83zh6akUTE8BynDs6RQSLB-Ey8zsmuVgG4KLh38sb-sNoxZGizcaBZ7QmCUQVEZlzBKlbKMpAqBCvSOizA0FD2LgWVBFa1UlJ1DYF-l0_-hC0xFvK3lsbZHriRizQA_KZqylQ9l9QFMQo3642MuAGGRCbzwkcC_0)
[^aerodynamics]: [Aerodynamic Characteristics of RNA concetration of SARS-CoV-2](https://www.biorxiv.org/content/10.1101/2020.03.08.982637v1.abstract)
-[^nelson]: [Nelson Laboratories: Viral Filtration Efficiency (VFE) at increased challenge level](https://gitlab.cba.mit.edu/pub/coronavirus/tracking/uploads/164d119b5a7a5751c685a6677378668a/ER_2235600_Attachment_5_Viral_Filtration_Efficiency.pdf)
+[^VFEreport]: [Nelson Laboratories: Viral Filtration Efficiency (VFE) at increased challenge level](https://gitlab.cba.mit.edu/pub/coronavirus/tracking/uploads/164d119b5a7a5751c685a6677378668a/ER_2235600_Attachment_5_Viral_Filtration_Efficiency.pdf)
+[^nelson]: [Nelson lab filtration test](https://www.nelsonlabs.com/testing/bacterial-viral-filtration-efficiency-bfe-vfe/?industry=medical-devices&category=protective-barriers-material-performance)
## needed for testing apparatus
- nebulizer for aerosolization
- - is a Collison nebulizer best?
- -
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+ - three-jet Collison nebulizer?
+- impinger for collection
+- wet and dry thermometer / hygrometer for humidity
+- andersen sampler?? could be nice to bin different size particles - six-stage viable particle cascade impactor
+-
+-
+-
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