Dr.K.Anguraj, Revathi.V.M, Dr.M.JamunaRani, Shalini Ashok, Ramya.M, Vinothini.S. “Distance Monitoring Alarm For Covid 19 Using Ultrasonic Sensor”. Annals of the Romanian Society for Cell Biology, Apr. 2021, pp. 11571-8, https://annalsofrscb.ro/index.php/journal/article/view/3977.