No Life Til Metal.com:
"Black Sabbath (n.) 1. heavy metal!"
"Heavy metal is forever indebted to the Sabs!"
"The metal brilliance of Geezer, Ozzy, Tony Iommi and Bill Ward continues on this their fourth disc."
"What an impact these first four albums have had on metal, it's actually quite amazing. Perhaps this is the reason there are no less than 10 tribute cds to this band."
http://nolifetilmetal.com/blacksab.htm