Grego, P. (2008). Venus and Mercury, and How to Observe Them. Springer New York. https://doi.org/10.1007/978-0-387-74286-1
Chicago-viite (17. p.)Grego, Peter. Venus and Mercury, and How to Observe Them. New York, NY: Springer New York, 2008. https://doi.org/10.1007/978-0-387-74286-1.
MLA-viite (9. p.)Grego, Peter. Venus and Mercury, and How to Observe Them. Springer New York, 2008. https://doi.org/10.1007/978-0-387-74286-1.
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