EntityFramework, Web Api, MVC Async Operation

http://stackoverflow.com/questions/29168188/asp-net-web-api-2-async-action-methods-with-task-run-performance

https://msdn.microsoft.com/en-us/data/jj819165.aspx

https://msdn.microsoft.com/ru-ru/library/hh191443.aspx

http://stackoverflow.com/questions/25204336/why-dbsettentity-doesnt-implement-enumerableasync

http://stackoverflow.com/questions/21631774/entityframework-dbcontext-and-using-async

http://www.asp.net/mvc/overview/performance/using-asynchronous-methods-in-aspnet-mvc-4

http://blog.stephencleary.com/2012/07/dont-block-on-async-code.html

https://www.simple-talk.com/dotnet/.net-framework/the-.net-4.5-asyncawait-feature-in-promise-and-practice/

http://blog.tonysneed.com/2013/03/22/async-services-asp-net-web-api-entity-framework-6/

http://www.c-sharpcorner.com/UploadFile/2b481f/create-asynchronous-action-method-in-web-api/