Unicode also has and , which have an appearance similar to the character. Typing the character Because the © symbol is not available on typical typewriters or in ASCII, it has long been common to approximate this symbol with the characters (c in parentheses), a practice that has been accepted by the U.S. Copyright Office under both the 1909 and 1976 U.S. Copyright Acts. Word processing software with an autocorrection facility can recognise this three-character sequence and convert it automatically to a single copyright symbol. On modern computer systems, the formal symbol can be generated using any of these methods: Windows: Mac: Linux: . ChromeOS: , , then or . HTML: or Related symbols The sound recording copyright symbol is the symbol ℗ (the capital letter P enclosed by a circle), and is used to designate copyright in a sound recording. The copyleft symbol is a backwards capital letter C in a circle (copyright symbol © mirrored). It has no legal meaning. See also Enclosed C Registered trademark symbol Trademark symbol Service mark symbol References Copyright law United States copyright law Typographical symbols Symbols introduced in 1909