Published in Revista de la Academia Canaria de Ciencias, in 1993, in volume 5, issue 4, pages 9-23

Published in Revista de la Academia Canaria de Ciencias, in 1993, in volume 5, issue 4, pages 25-58

Published in Revista de la Academia Canaria de Ciencias, in 1993, in volume 5, issue 4, pages 59-115

Published in Revista De La Academia Canaria De Ciencias, in 1993, in volume 5, issue 4, pages 127-152

Published in Revista De La Academia Canaria De Ciencias, in 1993, in volume 5, issue 4, pages 167-181