Two letters of Alexander Dubček and Oldřich Černík from June 1989 addressed to the Central Committee of the Polish United Workers’ Party and the government of the Polish People’s Republic

First Secretary of the Central Committee of the Communist Party of Czechoslovakia Alexander Dubček and Prime Minister of the Czechoslovak Socialist Republic Oldřich Černik, who held office during the Prague Spring of 1968, in an open letter to the Central Committee of the United Workers’ Party and the government of the Polish People’s Republic, advocate for a reform process in Czechoslovakia in 1968 and criticize the occupation of Czechoslovakia by the five Warsaw Pact states in August 1968, along with the subsequent normalization, which severely endangered the domestic and international authority of socialism.