1. A computer implemented method for providing a factuality: assessment of a retrieved information source's statement comprising: receiving a user's query which identifies an information source whose statements are to be retrieved; retrieving documents which refer to the information source; mapping statements in the retrieved documents to their authors; identifying as information source statements, the mapped statements that are mapped to an author which is compatible with the information source; for at least one of the information source's statements, assessing a factuality of the information source's statement according to the information source.