In any case the original ROTAX document in English language as well as the metric units (SI-system) contained therein are authoritative.
For relevant Airworthiness Directives (AD) see EASA Website and also check with your local civil aviation authority (e.g. EASA, FAA, TC, ...).
The documents are available and may be downloaded in Adobe pdf format. If you encounter difficulties with the pdf-files, make sure to have the latest updates installed for your version of Adobe® Reader®.