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. @calendar indicates the system or calendar to which the date represented by the content of this element belongs, but this element has no textual content. The @unit attribute may be unnecessary when @unitRef is present. The element should not be categorized in detail with @subtype unless also categorized in general with @type @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. Abstract model violation: Paragraphs may not occur inside other paragraphs or ab elements. Abstract model violation: Lines may not contain higher-level structural elements such as div, p, or ab. 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">. 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 Abstract model violation: Lines may not contain higher-level structural elements such as div. Abstract model violation: p and ab may not contain higher-level structural elements such as div. You must supply at least two values for @target or on Abstract model violation: ab may not occur inside paragraphs or other ab elements. Abstract model violation: Lines may not contain higher-level divisions such as p or ab. You must supply at least two values for @target on