Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. University of Pittsburgh.
Style de citation Chicago (17e éd.)Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. Lancaster, Pa: University of Pittsburgh.
Style de citation MLA (8e éd.)Não informado. Publications of the Allegheny Observatory of the University of Pittsburgh. University of Pittsburgh.
Attention : ces citations peuvent ne pas être correctes à 100%.