The @generatedBy attribute is for use within a <post> element. The @when attribute cannot be used with any other att.datable.w3c attributes. The @from and @notBefore attributes cannot be used together. The @to and @notAfter attributes cannot be used together. When there is more than one , each must have an @xml:id When there is more than one , one and only one must have a @default of 'true'. When used on a schema description element (like ), the @source attribute should have only 1 value. (This one has .) The @unit attribute may be unnecessary when @unitRef is present. @targetLang should only be used on if @target is specified. The element indicated by @spanTo () must follow the current element @schemeVersion can only be used if @scheme is specified. The element should not be categorized in detail with @subtype unless also categorized in general with @type @calendar indicates one or more systems or calendars to which the date represented by the content of this element belongs, but this element has no textual content. Abstract model violation: Paragraphs may not occur inside other paragraphs or ab elements. Abstract model violation: Metrical lines may not contain higher-level structural elements such as div, p, or ab, unless p is a child of figure or note, or is a descendant of floatingText. Information about a deprecation should only be present in a specification element that is being deprecated: that is, only an element that has a @validUntil attribute should have a child <desc type="deprecationInfo">. When target= is present, neither from= nor to= should be. When from= is present, the to= attribute of is required. When to= is present, the from= attribute of is required. Only one of the attributes @target and @cRef may be supplied on . Only one of the attributes @target and @cRef may be supplied on . The content of a "gloss" list should include a sequence of one or more pairs of a label element followed by an item element If the @target attribute on is used, the relatedItem element must be empty A relatedItem element should have either a @target attribute or a child element to indicate the related bibliographic item Abstract model violation: Lines may not contain lines or lg elements. An lg element must contain at least one child l, lg, or gap element. Abstract model violation: Lines may not contain line groups. On , either the @marks attribute should be used, or a paragraph of description provided An XPath in @match on the outer must start with '/'. An XPath in @match must not start with '/' except on the outer . Abstract model violation: Metrical lines may not contain higher-level structural elements such as div, unless div is a descendant of floatingText. Abstract model violation: p and ab may not contain higher-level structural elements such as div, unless div is a descendant of floatingText.