Published in Boletin De La Sociedad De Biologia De Concepcion, in 1969, in volume 40, pages 81-89

Published in Boletin Soc Biol Concepcion, in 1969, in volume 41, pages 5-8

Published in Boletin De La Sociedad De Biologia De Concepcion, in 1969, in volume 41, pages 41-78