This article is a list of standard proofreader's marks used to indicate and correct problems in a text. Marks come in two varieties, abbreviations and abstract symbols. These are usually handwritten on the paper containing the text. Symbols are interleaved in the text, while abbreviations may be placed in a margin with an arrow pointing to the problematic text. Note that different languages use different proofreading marks and sometimes publishers have their own in-house proofreading marks.