Complex sentence: After fulfilling this request and presenting a report, Cabrera felt inspired to extend it on his own; but as a courtesy, required a signed opinion of his work from his six colleagues, six professional statements which were also printed in both languages.
Split into simpler sentences: After fulfilling this request and presenting a report, Cabrera felt inspired to extend it on his own. As a professional courtesy, he required a signed opinion of his work from his six colleagues, six professional statements which were also printed in both languages.