The Tarlis and Petrich incidents triggered heavy protests in Bulgaria and international outcry against Greece. The Common Greco-Bulgarian committee for emigration investigated the incident and presented its conclusions to League of Nations in Geneva. As a result, a bilateral Bulgarian-Greek agreement was signed in Geneva on September 29, 1925, known as Politis-Kalfov protocol after the demand of the League of Nations, recognizing Greek Slavophones as Bulgarians and guaranteeing their protection. Next month a Slavic language primer textbook in Latin known as Abecedar published by the Greek ministry for education, was introduced to Greek schools of Aegean Macedonia. On February 2, 1925, the Greek parliament, under pressure from Serbia, rejected ratification of the 1913 Greek-Serbian Coalition Treaty. Agreement lasted 9 months until June 10, 1925, when League of Nations annulled it.