25912 civil procedure/ arbitration agreement Civil procedure code civil procedure contract of arbitration Federal supreme court of Ethiopia cassation decisions volume 5 የግልግል ስምምነት እንደመጨረሻ ፍርድ የሚቆጠር ስለመሆኑ የፍ/ብ/ህ/ቁ. 3312 Cassation Decision no. 25912