Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 60-61

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 66-75

Published in Jour Washington Acad Sci, in 1928, in volume 18, pages 96-102

Published in Jour Washington Acad Sci, in 1928, in volume 18, pages 145-158

Published in Jour Washington Acad Sci, in 1928, in volume 18, pages 177-178

Published in Jour Washington Acad Sci, in 1928, in volume 18, pages 194-196

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 197-200

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 233-241

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 241-249

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 249-253

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 306-313

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 316-317

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 381-382

Published in Jour Washington Acad Sci, in 1928, in volume 18, pages 421-430

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 561-563

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, pages 577-582

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 1, pages 5-10

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 2, pages 25-37

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 7, pages 178-186

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 8, pages 203-206

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 8, pages 216-226

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 10, pages 273-282

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 15, pages 430-433

Published in Journal of The Washington Academy of Sciences, in 1928, in volume 18, issue 18, pages 485-498