A package describes a tree-structured organization of DSs and Ds.
Packages support the concept of nesting in which packages can be embedded within packages.
International Organization for Standardization, International Standard 7498-4, 1991. International Organization for Standardization, International Standard 7498-4, 1991. Schemes XM - Description, Version et al. Schemes WD - Description, Version et al. The graph only includes citing articles where the year of publication is known.