Complex sentence: In 1967 Dr. Harold Eugene Edgerton worked with the American researcher Peter Throckmorton who were convinced that Helike lies on the seabed of the Gulf of Corinth.
Split into simpler sentences: In 1967 Dr. Harold Eugene Edgerton worked with the American researcher Peter Throckmorton. They were convinced that Helike lies on the seabed of the Gulf of Corinth.