No. 21 was not published. U.N. document series symbol: ST/CTC/SER.A/..., e.g. No. 20 carries document symbol ST/CTC/SER.A/20. Every Issue also carries a U.N. sales number in U.N. sales category II.A, e.g. No. 20 was assigned E.90.II.A.16. Beginning with [no.] 22, the appearance of the title page changed: the series title is not shown any more, nor is the issue identified as "Series A, No. ..."; the numbering of the series only continues in the document series symbol, e.g. no. 22 is symbolled ST/CTC/SER.A/22. At head of title page: United Nations Centre on Transnational Corporations.
No. 1-22 (1986-1992) STA No. 1-22 (1986-1992)