Abstract: There is provided, in accordance with an embodiment, a method comprising using one or more hardware processor for receiving two or more electronic documents from two or more computerized sources, where each of the electronic documents comprise alphanumeric text. A hierarchical mapping database is retreived, where the hierarchical mapping database comprises records that map between two or more map terms, each comprising two or more words, phrases, and codes, and between a tree structure of unique codes, where the tree structure comprises unique codes for each of at least four classes, and where each of the map terms is mapped to one of the unique codes. The electronic documents are screened to obtain a subset of electronic documents by locating a matching between some of the map terms in some of the classes. The subset is stored in a database on a non-transitory storage medium.