Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1915, in volume 66, pages 608-632

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 66, pages 634-648

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 2-24

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 43-92

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 93-95

Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1915, in volume 67, pages 96-106

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 108-192

Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1915, in volume 67, pages 203-243

Published in Proceed ings of the Academy of Natural Sciences, Philadelphia, in 1915, in volume 67, pages 244-269

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 270-292

Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1915, in volume 67, pages 293-322

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 351-362

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 419-425

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 458-514

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 520-546

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1915, in volume 67, pages 592

Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1915, in volume 1915, pages 29-35