Complex sentence: An extensive revision, the "Grammata Serica Recensa", appeared in 1957 and included the results of Karlgren's studies of pre-Han texts ans indicated tones, which had been omitted in the first version.
Split into simpler sentences: An extensive revision incorporating the results of Karlgren's studies of pre-Han texts, the "Grammata Serica Recensa", appeared in 1957. It also indicated tones, which had been omitted in the first version.