The coup plotters called their operation the 30th September Movement (Gerakan Tiga Puluh September, later abbreviated G30S, but the Suharto forces soon gave it the more sinister abbreviation 'Gestapu'. Sukarno later insisted that, because the movement had actually begun its action on 1 October, it should be called Gestok (Gerakan Satu Oktober). More recently, the term 'Gestok' has been applied to Suharto's counter-coup against the G30S.
Anderson, Benedict R.O'G., and Ruth T. McVey, A preliminary analysis of the October 1, 1965, coup in Indonesia. Ithaca, NY: Cornell University Modern Indonesia Project, 1975.
Crouch, Harold, The army and politics in Indonesia. Ithaca, NY: Cornell University Press, 1978
Roosa, John, Pretext for Mass Murder: The September 30th Movement and Suharto's Coup d'Etat in Indonesia. Madison: University of Wisconsin Press, 2007.
Wertheim, W.F., ‘Suharto and the Untung Coup: The Missing Link', Journal of Contemporary Asia, 1 no 2 (1970), pp. 50-57.