Published in Philippine Journal of Science, in 1914, in volume 8, pages 293-299
Published in Philippine Journal of Science, in 1914, in volume 8, pages 305-332
Published in Philippine Journal of Science, in 1914, in volume 9, pages 269-283
Published in Philippine Journal of Science, in 1914, in volume 9, pages 285-311
Published in Philippine Journal of Science, in 1914, in volume 9D, pages 57