Citation abbreviations are commonly used in academic writing to refer to sources. IBID is an abbreviation for the Latin phrase 'ibidem, ' which means 'in the same place.' It is used to refer to a source that has already been cited in the same work. ETAL is an abbreviation for the Latin phrase 'et alii, ' which means 'and others.' It is used to refer to multiple authors of a source. ETSEQ is an abbreviation for the Latin phrase 'et sequentes, ' which means 'and the following.' It is used to refer to multiple sources that have been cited in the same work.