TY - RPRT TI - Letter Circular 378b: zoned municipalities -- by population groups; municipalities of more than 40,000 and less than 100,000 population PY - 1933 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - LCIRC 378b DO - 10.6028/NBS.LCIRC.378b ER -