Only a small part of their music was progressive rock.
Thus, this piece can be considered an early example of progressive rock.
Progressive rock experienced a high degree of commercial success during the early 1970s.
The album as a whole was a return to progressive rock for the band.
They also blend into their music elements of progressive rock.
Rod nodded, and off they went after the progressive rock.
It has been described as progressive rock and heavy pop.
The band started playing blues but later changed to progressive rock.
Their music also had some progressive rock and classical influences.
The music of the album is commonplace in early 70's progressive rock.
