Published in Journal of The Washington Academy of Sciences, in 1918, in volume 8, pages 60-63

Published in Journal of The Washington Academy of Sciences, in 1918, in volume 8, pages 361-367

Published in Journal of The Washington Academy of Sciences, in 1918, in volume 8, pages 427-431

Published in Washington Dc J Acad Sci, in 1918, in volume 8, pages 431-448

Published in Washington Dc J Acad Sci, in 1918, in volume 8, pages 571-572

Published in Journal of the Washington Academy of Sciences, in 1918, in volume 8, pages 643-657

Published in Journal of The Washington Academy of Sciences, in 1918, in volume 8, issue 3, pages 58-60

Published in Journal of The Washington Academy of Sciences, in 1918, in volume 8, issue 19, pages 613-620