Hi Debra, the only way sources get added is by users. A source might get duplicated if it is on two profiles that then get merged and the person doing the merge doesn't remove the duplicated info. Or sometimes people will add a version of a source that is free to access, if the one already on the profile is from a pay site like Ancestry. Wikitree is a collaborative site so we shouldn't be preventing people from adding sources. If it is an exact duplicate, just remove it.