1 2
What is correct: "In 1960 Harary formulated the cell growth ... formulated the cell growth problem as a graph enumeration problem"?

Either looks fine to me. Mike Hardy

How about:
"In 1960 Harary reformulated the cell growth problem as a problem in graph enumeration"

Colin Rosenthal Sabbagh's Second Law: The biggest problem with communication is the illusion that it has occurred.