There are several different databases in EI retrieval, among which Compendex is the database of EI itself, and its retrieval number is 14, starting with the year; The retrieval number of Inspec database is 8 digits.

We generally say that "being included by EI" means being included in the database of Compendex, so the retrieval number 14 is correct.

By the way, Inspec is a database edited by the British Institute of Electrical Engineers. Although articles included in INSPEC can also be retrieved by EI, they are not strictly EI, that is to say, "retrieved by EI" does not mean "included by EI". Of course, there are many cases where both Compendex and Inspec are included. As mentioned above, the search number of 14 of Compendex shall prevail.