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2. Fitbit: One & Zip Wireless Activity & Sleep Tracker 2014. http://www.fitbit.com/. Fitbit: One & Zip Wireless Activity & Sleep Tracker 2014. http://www.fitbit.com/.
3. FitLinxx: Professional Fitness Tracking System 2014. http://www.fitlinxx.net/. FitLinxx: Professional Fitness Tracking System 2014. http://www.fitlinxx.net/.
4. Mayo Clinic Fitness Multimedia 2014. http://www.mayoclinic.org/healthy-living/fitness/multimedia/HLV-20049447?s=9. Mayo Clinic Fitness Multimedia 2014. http://www.mayoclinic.org/healthy-living/fitness/multimedia/HLV-20049447?s=9.
5. Polar: Heart Rate Monitors and GPS Enabled Sport Watches 2014. http://www.polar.com/. Polar: Heart Rate Monitors and GPS Enabled Sport Watches 2014. http://www.polar.com/.