`$R{<name>}` is replaced by the text of the resource with that name, in the language of the reader. A resource is a piece of text held in the model instead of in the template, with a value per language. It exists for two reasons: a sentence which occurs in several places is then written once, and a template which has to appear in more than one language keeps one text rather than one per language. A resource carries a name, a description, a language and a value; see [[Edit Model]]. There is one entry per language for the same name, and which of them is used follows the language of the person composing the document. A resource may itself hold markers, including another `$R{...}`, and those are resolved as well. That allows a standard clause to be assembled from smaller ones. A resource which refers to itself, directly or through another, is an error rather than an endless document.