Paul G. Richards
https://www.ldeo.columbia.edu/~richards
https://www.ldeo.columbia.edu/~richards/PGRc.v.long.html
Last updated August 25, 2020
https://www.ldeo.columbia.edu/~richards
https://www.ldeo.columbia.edu/~richards/PGRc.v.long.html
Last updated August 25, 2020