Não informado. (2021). Information Services & Use. North-Holland Publishing Company.
Chicago-viite (17. p.)Não informado. Information Services & Use. Amsterdam: North-Holland Publishing Company, 2021.
MLA-viite (8. p.)Não informado. Information Services & Use. North-Holland Publishing Company, 2021.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.