Lev Manovich
What comes after remix? - published in 2007
In his essay Lev Manovich uses a lot of examples for remixing and sampling, explains about how it used to be known as 'quoting' but now that reference is not applicable to remixing as remixing is a new practice of authorship.
He also reviews the development of remix culture and the key to the success within the public's participation with the introduction of new software such as Photoshop and After Effects making remixing more open to none designers.
He also addresses the fact that most artists now conceive their work beforehand as a prospect for others to remix and modify the work as often remixes are very successful.
Manovich then concludes his essay with:

"What happens next? Will we still be able to create aesthetics that do not rely on excessive sampling?

What he addresses here is the scale in which remix culture has taken of the current time and is constantly evolving and expanding, how people are constantly testing the rights of work and where the authorship lies.
Here is an example I found which reiterates what Lev Manovich portrays in his essay. The top image is an original piece of graphic commercial work by A.M Cassandre, a Dubonnet advertisement from the 1930’s, which has then been modernized for the image below and ‘remixed’ by Alan Fletcher from D&DA, a design group in London for a 21st anniversary in 1983.