THE HELIOS OPERATING.. (1989). The helios operating system: Perihelion software ltd. Prentice Hall.
Čikaški stil citiranja (17. izdanje)THE HELIOS OPERATING.. The Helios Operating System: Perihelion Software Ltd. New York: Prentice Hall, 1989.
MLA način citiranja (9. izdanje)THE HELIOS OPERATING.. The Helios Operating System: Perihelion Software Ltd. Prentice Hall, 1989.
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