PT  - JOURNAL ARTICLE
AU  - Hitchcock, R.
TI  - The causes of variation
AID  - 10.2475/ajs.s3-28.163.49
DP  - 1884 Jul 01
TA  - American Journal of Science
PG  - 49--52
VI  - s3-28
IP  - 163
4099  - http://www.ajsonline.org/content/s3-28/163/49.short
4100  - http://www.ajsonline.org/content/s3-28/163/49.full
SO  - Am J Sci1884 Jul 01; s3-28