In scientific articles, the ways authority is used in texts are not analysed in terms of the Information Science. Grey literature mostly concentrates on published works by analysing citations to measure statistically their influence. Starting with definitions that have been established in different disciplines, we propose to frame authority according to its means of expression. The first one concerns recognised social entities that can be broken down into enunciative authority and institutional authority. The epistemic and cognitive authority concerns knowledge, media exposure of texts takes place under the authority of the software used and the authority of the intended audience. An initial application of this analytical grid thus set up indicates that these three ways of framing authority can overlap each other without precluding the objectives pursued by the authors.