Industrial development in Lazio is limited to the areas south of Rome. Communications and - above all - the setting of the border of the Cassa del Mezzogiorno some kilometers south of Rome, have influenced the position of industry, favouring the areas with the best links to Rome and those near the Autostrada del Sole (motorway), especially around Frosinone. Firms are often small to medium in size and operate in the building and building materials (Rome, Civitavecchia), paper (Sora, Italy, Isola del Liri), petrochemical (Gaeta, Rome), textile (Frosinone), engineering (Rieti, Anagni), automobile (Cassino), electronic and electrotechnical (Viterbo) sectors.