1. Cress. http://borgwaldt.hauni.com/en/instruments/smoking-machines/smoking-topograph%y-devices/cress-pocket.html. Cress. http://borgwaldt.hauni.com/en/instruments/smoking-machines/smoking-topograph%y-devices/cress-pocket.html.
2. Cdc fact sheet on smoking. http://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/. Cdc fact sheet on smoking. http://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/.
3. Using mobile phones to write in air
4. mPuff