RT Book, Section SR Electronic(1) A1 United Nations YR 1991 T1 International Telecommunication Union (ITU) T2 Yearbook of the United Nations 1991 PB United Nations SN 9789210578080 DO 10.18356/cbabbce2-en UL https://www.un-ilibrary.org/content/books/9789210578080s012-c012