Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. University of Pittsburgh.
Čikaški stil citiranja (17. izdanje)Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. Lancaster, Pa: University of Pittsburgh.
MLA način citiranja (8. izdanje)Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. University of Pittsburgh.
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