求3篇英文文献，5币一篇。

1、Optimal demand for operating lease of aircraft
2、Aircraft replacement scheduling: A dynamic programming approach
3、Asset liquidity and financial contracts: Evidence from aircraft leases

文献来源：www.sciencedirect.com

现在没有，不好意思啦，如果能找到，再传上来~

first paper

third paper!

second paper

第1和3篇没有正式发表的版本么？好像是discussing paper?