The subfonds contains copies of outgoing mail as well as the IBI’s incoming and outgoing correspondence (letters and telexes). There are gaps in each of the series in the subfonds: IBI/5/1/1 Originals, IBI/5/1/2 Outgoing, and IBI/5/1/3 Telexes and telegrammes. For series IBI/5/1/1 Originals, mail is missing prior to the last trimester of 1982. After this time, the series is relatively complete and regular until the first trimester of 1988. Series IBI/5/1/2, Outgoing correspondence, is more fragmented and incomplete and does not contain any documents prior to 1983. Series 5/1/3 contains only a few files of incoming telexes and telegrams for the years 1986-1987.