1. http~://www.gsmarena.com/samsung_i9505_galaxy_s4-5371.php. http~://www.gsmarena.com/samsung_i9505_galaxy_s4-5371.php.
2. http~://www.gsmarena.com/samsung_galaxy_s6_edge+-7467.php. http~://www.gsmarena.com/samsung_galaxy_s6_edge+-7467.php.
3. http~://www.gsmarena.com/lg_nexus_5-5705.php. http~://www.gsmarena.com/lg_nexus_5-5705.php.
4. Google maps tells how bas the parking is at your destination. http://mashable.com/2017/01/18/google-maps-finds-parking-spots/#LafUADIWnaq3. Google maps tells how bas the parking is at your destination. http://mashable.com/2017/01/18/google-maps-finds-parking-spots/#LafUADIWnaq3.
5. Parking sensor performance standards and measurement. http://sfpark.org/wp-content/uploads/2011/09/SFpark_SensorPerformance_v01.pdf. Parking sensor performance standards and measurement. http://sfpark.org/wp-content/uploads/2011/09/SFpark_SensorPerformance_v01.pdf.