The ma jor-source code and fields l 10 10. inclusive, were punched from the schedule. The major source was coded on the schedule by encircling the largest of the value- of- products entries or by entering a aquot;V, aquot; if ... The trailer and special control punches were used to prevent duplications of this acreage in the tabulations.
|Title||:||Sixteenth Census of the United States: 1940. Agriculture Handbook|