Complex sentence: From 1967 to 1970, Johnny Stark was also responsible for the career of singer Michel Delpech and in 1976, he organized François Valéry's tour with Johnny Mathis at more than 60 venues across France.
Split into simpler sentences: From 1967 to 1970, Johnny Stark was also responsible for the career of singer Michel Delpech. In 1976, he organized François Valéry's tour with Johnny Mathis at more than 60 venues across France.