(1988). Variable spectra of active galaxies: Final technical report / prepared by Jules P. Halpern.
Čikaški stil citiranja (17. izdanje)Variable Spectra of Active Galaxies: Final Technical Report / Prepared by Jules P. Halpern. 1988.
MLA način citiranja (9. izdanje)Variable Spectra of Active Galaxies: Final Technical Report / Prepared by Jules P. Halpern. 1988.
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