Context: In July 1963 the Mongolian People's Republic asked to join the Warsaw Pact under Article 9 of the treaty. For this purpose a special protocol should have been taken since the text of the treaty applied only to Europe. Due to the emerging Sino-Soviet split, Mongolia remained on observer status. Soviet stationing troops were agreed to stay in Mongolia from 1966.

Question: In which year did Mongolia seek entry in the Warsaw Pact?
Answer: 1963

Question: In which year were Soviet forces scheduled to leave Mongolia? 
Answer: 1966

Question: Who asked to join the Warsaw Pact in January 1963?
Answer: Unanswerable

Question: Who asked to join the Warsaw Pact under Article 10?
Answer: Unanswerable

Question: Which group was removed from observer status?
Answer: Unanswerable

Question: Whose troops agrees to stay in Mongolia from 1956?
Answer: Unanswerable