请问有谁知道70年代petra乐队的资料

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Petra is one of the most successful Christian rock bands ever, a veritable institution whose name (taken from the Greek word for "rock") has come to reflect not only their music, but their staying power as well, even in spite of Christian radio's reluctance to program their brand of loud, slick arena-rock. Petra was formed in 1972 by guitarist Bob Hartman, who was attending the Christian Training Center in Fort Wayne, Indiana at the time; he recruited several fellow students — guitarist/vocalist Greg Hough, bassist John DeGroff, and drummer Bill Glover — to his cause, and the group began playing around the Fort Wayne area with backing from their school. Petra encountered early resistance to the very idea of Christian rock from many local churches, who held that the rock