Complex sentence: In his book "Mind Race", Targ wrote that with Harary he had predicted prices on the silver market at Delphi Associates and claimed to have correctly predicted all nine forecasts that they made in 1982; however, a later attempt failed.
Split into simpler sentences: In his book "Mind Race", Targ wrote that with Harary he had predicted prices on the silver market at Delphi Associates. Targ claimed to have correctly predicted all nine forecasts that they made in 1982, however, a later attempt failed.