 Complete the following phrase:  Mariya Dimitrova Petkova , née Vergova ; born 3 November 1950 in Plovdiv is a retired Bulgarian discus thrower. In 1976 she won an Olympic silver medal behind Evelin Schlaak, a standing that would repeat itself in 1980. This year she also achieved a personal best throw of 71.80 metres. In 1982 she won a European Championship silver medal behind countrywoman Tsvetanka Khristova, who is twelve years younger. One year later Petkova won the bronze medal at the first 