@deisydavi, all the schools, have text from Ananda, "What The Buddha Said," but many disagree on the order of the text written down, and the Chinese Agamas were copied from Buddhist Sanskrit text. Some suttas are missing, but all in all the words of Buddha were faithfully kept in all the surviving schools we have today. What differs from school to school is the Vinaya, codes of the monastics and the Abhidhamma which is post-canonical, written after Buddha's Paranirvana.