RT Journal Article SR Electronic T1 The alpha-gamma transformation of iron at high pressures, and the problem of the earth's magnetism JF American Journal of Science JO Am J Sci FD American Journal of Science SP 192 OP 211 DO 10.2475/ajs.238.3.192 VO 238 IS 3 A1 Birch, Albert Francis YR 1940 UL http://www.ajsonline.org/content/238/3/192.abstract AB