Published in Commercial handbook of the Philippine islands, 1924.

Published in Commercial handbook of the Philippine Islands.

Published in Geology and Mineral Resources of the Philippine Islands.

Published in Yearbook of the Philippine Island 1950.

Published in Our islands and their people.

Published in Our islands and their people.

Published in Our islands and their people.

Published in Our islands and their people.

Published in Our islands and their people.

Published in Our islands and their people.