original: it was discovered in 1907 by august kopff .
simplifications: it was discovered in 1907 by august kopff . it was invented in 1907 by august kopff . it was determined in 1907 by august kopff . it was found in 1907 by august kopff . it was discovered in 1907 by august kopff . august kopff discovered it in 1907 . discovered in 1907 by august kopff it was found in 2907 by august kopff .