Question:  "Mandrake Root" is a song by the globe's loudest band as listed in what book from 1975?

Related documents: [0]  [DOC] Deep Purple are an English rock band formed in Hertford in 1968. The band is considered to be among the pioneers of heavy metal and modern hard rock, although their musical approach changed over the years. Originally formed as a progressive rock band, the band shifted to a heavier sound in 1970. Deep Purple, together with Led Zeppelin and Black Sabbath, have been referred to as the "unholy trinity of British hard rock and heavy metal in the early to mid-seventies". They were listed in the 1975 "Guinness Book of World Records" as "the globe's loudest band" for a 1972 concert at London's Rainbow Theatre, and have sold over 100 million albums worldwide. [END] 
[1]  [DOC] "Mandrake Root" is a song by Deep Purple that is featured on their debut album "Shades of Deep Purple". The title is in reference to the mandrake plant, but is also the name of a pre-Purple band that Blackmore was trying to form in Germany when he got the call from Deep Purple's original management. [END]  
Answer: Guinness Book of World Records
Guinness Book of World Records