Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 1-3

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 25-28

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 35-41

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 59-60

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 82-83

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 83-84

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 87-88

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 107-114

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 116-117

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 225-241

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 317-331

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 331-340

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 370-372

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 381-384

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 395-396

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 398-418

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 421-432

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 432-434

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 434-435

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 465-475

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, pages 488-495

Published in Jour Washington Acad Sci, in 1930, in volume 20, pages 501-509

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, issue 2, pages 484-488

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, issue 15, pages 372-374

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, issue 15, pages 374-381

Published in Journal of The Washington Academy of Sciences, in 1930, in volume 20, issue 16, pages 396-398