Published in Proceedings of the Academy of Natural Sciences of Philadelphia, in 1919, in volume 71, pages 2-15
Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1919, in volume 71, pages 55-120
Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1919, in volume 71, pages 121
Published in Proceedings of the Academy of Natural Sciences, Philadelphia, in 1919, in volume 71, pages 125-127
Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1919, in volume 71, pages 206
Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1919, in volume 71, pages 306-312
Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1919, in volume 71, pages 317-323