Implementation phase of an SDLC

I need 4 quality references.  References need to be current 2015-2018 and web based.  no google books and no books all from the web with a working website so I and the professor can go to the web and see the information.

1 page not including references single spaced. 

Why would someone use the parallel method for the implementation phase of an SDLC if I they were to managing a project.