Citations
First day cover from the Royal Greenwich Observatory with all four Halley’s Comet stamps affixed, 1986-02-18, GBR/0180/RGO 97/5/3. Cambridge University Library. |
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First day cover from the Royal Greenwich Observatory with all four Halley’s Comet stamps affixed, 1986-02-18, GBR/0180/RGO 97/5/3. Cambridge University Library. https://archivesearch.lib.cam.ac.uk/repositories/2/archival_objects/146792 Accessed May 10, 2024. |