Dostupné online. https://www.space.com/16623-first-powered-airship.html The First Powered Airship | The Greatest Moments in Flight The First Powered Airship | The Greatest Moments in Flight dirigible balloons https://www.space.com/16623-first-powered-airship.html The First Powered Airship | The Greatest Moments in Flight steam-powered airship https://www.space.com/16623-first-powered-airship.html