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- Hermann Oberth, Romanian rocket scientist (1975)
- Manoel de Oliveira, film director (2008)
- Joaquim Pedro de Oliveira Martins, historian and politician (1994)
- Our Lady of Fátima (1950; 1967)
- Our Lady of the Conception (1946; 1997)
Read more about this topic: List Of People On Stamps Of Portugal