The Document Style Semantics and Specification Language (DSSSL) is an international standard developed to provide stylesheets for SGML documents. DSSSL consists of two parts: a tree transformation process that can be used to manipulate the tree structure of documents prior to presentation, and a formatting process that associates the elements in the source document with specific nodes in the target representation—the flow object tree. DSSSL specifications are device-independent pieces of information that can be interchanged between different platforms. DSSSL does not standardize the back-end formatters that generate the language's output. Such formatters may render the output for on-screen display, or write it to a computer file in a specific format (such as PostScript or Rich Text Format.