Nevertheless much pop and rock music has been very similar in sound, instrumentation and even lyrical content. The terms "pop-rock" and "power pop" have been used to describe more commercially successful music that uses elements from, or the form of, rock music. Pop-rock has been defined as an "upbeat variety of rock music represented by artists such as Elton John, Paul McCartney, The Everly Brothers,Rod Stewart, Chicago, and Peter Frampton." In contrast, self-published music reviewer George Starostin defines it as a subgenre of pop music that uses catchy pop songs that are mostly guitar-based. Starostin argues that most of what is traditionally called "power pop" falls into the pop rock subgenre and that the lyrical content of pop rock is "normally secondary to the music." The term power pop was coined by Pete Townshend of The Who in 1966, but not much used until it was applied to bands like Badfinger in the 1970s, who proved some of the most commercially successful of the period. Throughout its history there have been rock acts that have used elements of pop, and pop artists who have used rock music as a basis for their work, or striven for rock "authenticity".