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Prévot, Marie-Louise; Caplan, James (1998). "History of the Marseille Observatory". Acta Historica Astronomiae. 3: 78. Bibcode:1998AcHA....3...78P. ISSN0003-2670.
Friedjung, M. (1971). "1971JBAA...81..479F Page 479". Journal of the British Astronomical Association. 81. Bibcode:1971JBAA...81..479F.
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heurelegalefrancaise.fr
French legal time "French legal time is generated and provided by Observatoire de Paris as part of its missions and in agreement with Decree No. 2017-292 of March 6, 2017 defining French legal time. Legal time is constructed from UTC(OP), which is the real-time realization of UTC at Observatoire de Paris."
Prévot, Marie-Louise; Caplan, James (1998). "History of the Marseille Observatory". Acta Historica Astronomiae. 3: 78. Bibcode:1998AcHA....3...78P. ISSN0003-2670.