Additional reading on compulsory jurisdiction, including further details of optional clause:
TOWARDS COMPULSORY JURISDICTION: CONTEMPORARY INTERNATIONAL TRIBUNALS AND DEVELOPMENTS IN THE INTERNATIONAL RULE OF LAW ANTÔNIO AUGUSTO CANÇADO TRINDADE, accessed through the Organisation of American States, Part I (https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.oas.org/es/sla/ddi/docs/publicaciones_digital_XXXVII_curso_derecho_internacional_2010_Antonio_Augusto_Cancado_Trindade.pdf&ved=2ahUKEwj0kaPe8qWMAxV0q5UCHeK6OfsQFnoECC4QAQ&usg=AOvVaw0NKXOWSeYUdnfmpKOoyt93)
and Part II (https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.oas.org/es/sla/ddi/docs/publicaciones_digital_XXXVIII_curso_derecho_internacional_2011_Antonio_Augusto_Cancado_Trindade.pdf&ved=2ahUKEwj0kaPe8qWMAxV0q5UCHeK6OfsQFnoECEsQAQ&usg=AOvVaw2IZ3WXFkNxohGxVqbvWT2X)