Complex sentence: They were among the authors of dictionaries who opposed the protests of 1968 and were written in the style of "Eckardt Henscheids Dummdeutsch" dictionary (dealing with language criticism).
Split into simpler sentences: They were among the authors of dictionaries opposing the protests of 1968. These dictionaries were written in the style of "Eckardt Henscheids Dummdeutsch" dictionary (dealing with language criticism).