ISBN 9781425137076 books & textbook
The Piasecki H-21 Helicopter: An Illustrated History of the H-21 Helicopter and Its Designer, Frank N. Piasecki
Robert J. Brandt William J. Davies
Trafford Publishing /2007-10-30 Paperback / 176 Pages
isbn-10: 1425137075 / isbn-13: 9781425137076
