"The main use of an apostrophe is to denote possessive ownership of something, usually with an \"s\" following the apostrophe. For example: \"Dan's cats escaped the building.\" However, if the possessor's name ends with the letter \"s,\" the apostrophe can stand alone with no \"s\" needed. This is the correct usage: '\"Janus' cats escaped the building.\" This common usage is incorrect: \"Janus's cats escaped the building.\""@en . . "The main use of an apostrophe is to denote possessive ownership of something, usually with an \"s\" following the apostrophe. For example: \"Dan's cats escaped the building.\" However, if the possessor's name ends with the letter \"s,\" the apostrophe can stand alone with no \"s\" needed. This is the correct usage: '\"Janus' cats escaped the building.\" This common usage is incorrect: \"Janus's cats escaped the building.\""@en . . "Community Grammar Guide"@en .