Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 11-27

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 29-30

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 30-37

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 53-59

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 59-63

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 63-66

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 125-127

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 135-142

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 142-145

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 145-148

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 148-150

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 155-159

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 159-166

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 195-197

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 199-200

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 235-240

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 241-245

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 281-282

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 283-286

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 300-301

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 303-304

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 337-339

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 339-347

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 357-305

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 425-428

Published in Jour Washington Acad Sci, in 1929, in volume 19, pages 428-434

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 435-436

Published in Journal of the Washington Academy of Sciences, in 1929, in volume 19, pages 436-440

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 460-462

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, pages 469-472

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, issue 13, pages 268-281

Published in Journal of The Washington Academy of Sciences, in 1929, in volume 19, issue 15, pages 327-337