Italian National Institute of Statistics. Retrieved 16 March 2019. ↑ All demographics and other statistics: Italian statistical institute Istat. ↑ "Labro". Matre Terra (in Italian). ↑ Francesco Palmegiani, Rieti e la Regione Sabina, Rome, edizioni della rivista Latina Gens, 1932, page 387. ↑ "La storia - il recupero" (in Italian).