1. Porter O-Two.
https://www.porterinstrument.com/product/dental/Porter-O-Two
. Accessed 11 Mar 2019.
2. Porter-Emergency-Oxygen-Brochure-FM-956.
http://www.porterinstrument.com/dentalcontent/files/datasheets/Porter-Emergency-Oxygen-Brochure-FM-956.pdf
.
3. Porter In-Line Vacuum Control.
https://www.porterinstrument.com/product/dental/Porter-In-Line-Vacuum-Control
. Accessed 11 Mar 2019.
4. Porter Automatic Vacuum Switch.
https://www.porterinstrument.com/product/dental/Porter-Automatic-Vacuum-Switch
. Accessed 11 Mar 2019.
5. Porter MXR-1 Cabinet-Mounted Flowmeter.
https://www.porterinstrument.com/product/dental/Porter-MXR-1-Cabinet-Mounted-Flowmeter
. Accessed 11 Mar 2019.