Dwelling 4 : A building occupied with no more than two living units, each of which is occupied by a family; no more than three outsiders may rent rooms
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}