Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 1

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 205

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 207-230

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 231-250

Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1917, in volume 69, pages 251-275

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 279

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 305-308

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, pages 346-353

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1917, in volume 69, issue 1, pages 2-6