Signature of the Lisbon Agreement (1958) by the Czechoslovak Republic: April 17, 1959; Ratification by the Czechoslovak Socialist Republic: August 11, 1961; Entry into force: September 25, 1966. Accession to Stockholm Act (1967): September 22, 1970; Entry into force: October 31, 1973. Declaration of continued application by the Czech Republic: December 18, 1992. Entry into force date given as date of independence.