Internal entities offer a convenient solution to these problems. Instead of typing the same text over and over again, you can define an internal entity to contain the text and then you only need to use the entity where you want to insert the text. Because the entity is expanded by the parser, you can be assured that you'll get the same text in every location. Character References Character references, which are similar in appearance to entity references, allow you to reference arbitrary Unicode characters, even if they aren't available directly on your keyboard. Character references are not properly entities at all.
Character references are numeric and can be used without any special declaration.
A character reference inserts the specified Unicode character directly into your document. Note that this does not guarantee that your processing or display system will be able to do anything useful with the character. Whether or not you can print that character is an entirely different issue. Character references differ from other entity references in a subtle but significant way. They are expanded immediately by the parser.