Coxsone Dodd
Grennan is also remembered for his work at Studio One (Coxsone Dodd), Treasure Isle (Duke Reid), Federal, and Beverly's (Leslie Kong) although he also recorded with Sonia Pottinger, Clive Chin, Byron Lee and Winston Riley, and nearly every other record producer of the era. Early album releases rarely attributed the players of instruments and the majority of Grennan's early work was uncredited.