Papers published at international conferences will have collections and serial numbers to prove their publication. Generally, the collection will be released about 2 months after the press conference, while EI retrieval is generally 3- 12 months after the collection is officially released (some may take longer). Moreover, the publication of the portfolio does not mean that it will be retrieved by EI, and it may not be retrieved. If it is published by IEEE, it is more likely to be retrieved (above 90%).