ISO 2711 is an ISO standard describing formats for ordinal dates. The ISO is an international standard-setting body composed of representatives from various national standards organizations. ISO 2711 was issued in 1973, and was superseded by ISO 8601 in June 1988.[1]
Annex A … Identification of a particular date by means of ordinal dates (ISO 2711) and by means of the week numbering system (ISO 2015) were alternative methods that the basic concept of this International Standard could also encompass; thus, ISO 2015 and ISO 2711 have now been superseded.