Source:http://linkedlifedata.com/resource/umls/id/C1552923
NCI: An imperial unit of area equal the area of a square of one mile in length on each side. It is equal to 2.589988 square kilometers, 640 acres, or 3097600 square yards, or 1/36 of a township.,HL7V3.0: <p>1 [mi_us]2</p>