This author has not been identified. Look up 'Karl Karu' in GoogleThis author has not been identified. Look up 'Anton Ruzanov' in GoogleThis author has not been identified. Look up 'Heigo Ers' in GoogleThis author has not been identified. Look up 'Vladislav Ivanistsev' in GoogleThis author has not been identified. Look up 'Isabel Lage-Estebanez' in GoogleThis author has not been identified. Look up 'José Manuel García de la Vega' in Google