Published in Boletin De La Sociedad De Biologia De Concepcion, in 1976, in volume 50, pages 103-111

Published in Boletin De La Sociedad De Biologia De Concepcion, in 1976, in volume 50, pages 113-121

Published in Boletin Soc Biol Concepcion, in 1976, in volume 50, pages 173-181