RT Journal Article SR Electronic T1 ADRIAN JOHN PIETERS JF Science JO Science FD American Association for the Advancement of Science SP 610 OP 611 DO 10.1126/science.91.2374.610 VO 91 IS 2374 A1 KEPHART, L. W. YR 1940 UL http://science.sciencemag.org/content/91/2374/610.abstract AB