Published in Philippine Journal of Science, in 1916, in volume 11, pages 219-233

Created: 2012-12-07, modified: 2012-12-07

Published in Philippine Journal of Science D, in 1916, in volume 11, pages 347-350

Created: 2017-05-31, modified: 2017-05-31

Published in Philippine Journal of Science, in 1916, in volume 11, pages 387-398

Created: 2012-12-07, modified: 2012-12-07