1. WhatsApp.WhatsApp Messenger and Collaboration Tool.https://www.whatsapp.com. Accessed on April 10 2018.
2. Facebook.Facebook Messenger.https://www.messenger.com/. Accessed on April 10 2018.
3. Google.Google Hangout.https://hangouts.google.com/. Accessed on April 10 2018.
4. Microsoft.Enterprise capabilities with Skype for Business in Office 365.http://products.office.com/en-us/skype-for-business/online-meetings. Accessed on April 10 2018.
5. Cisco.Cisco Hosted Collaboration Solution (HCS).http://www.cisco.com/web/solutions/hcs/index.html. Accessed on April 10 2018.