"Purchase Planning Handbook"(PDF). Business & Commercial Aviation. Aviation Week Network. June 2019. Archived from the original(PDF) on 2020-05-10. Retrieved 2019-07-18.
"Purchase Planning Handbook"(PDF). Business & Commercial Aviation. Aviation Week Network. June 2019. Archived from the original(PDF) on 2020-05-10. Retrieved 2019-07-18.