Execute Tasks in Background

Task Perform in Background tutorials

http://mobile.tutsplus.com/tutorials/iphone/ios-7-sdk-mutlitasking-enhancements/

http://stackoverflow.com/questions/18247808/what-is-the-proper-way-to-handle-background-tasks-in-ios

http://www.xcubelabs.com/blog/ios-7-background-execution-and-multitasking/

http://www.xcubelabs.com/blog/ios-7-background-execution-and-multitasking/

http://www.objc.io/issue-5/multitasking.html

https://developer.apple.com/library/ios/documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html

http://www.techotopia.com/index.php/IOS_7_Multitasking,_Background_Transfer_Service_and_Fetching