Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 2-6

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 13-19

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 20-24

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 24-26

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 26-28

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 103-109

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 110-113

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 114-120

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 120-123

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 175-184

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 189-193

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 194-196

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 205

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 239-246

Published in Journal of The Washington Academy of Sciences, in 1971, in volume 61, pages 266-271