 Complete the following phrase:  There have been five motor racing drivers from Portugal who have participated in a Grand Prix event of the Formula One World Championship, three of which have started in a race. The first to be officially listed as an entrant was Casimiro de Oliveira at the 1958 Portuguese Grand Prix, though Mário de Araújo Cabral was the first driver to take part in a Formula One race, doing so at the 