https://www.uncrownedgaming.com/forums/topic/5026-full-list-of-official-booking-com-contact-numbers-in-the-usa-a-complete-guide/

https://w.atwiki.jp/sadfasdf23/pages/22.html

https://metalarea.org/forum/index.php?showtopic=419111

https://metalarea.org/forum/index.php?showtopic=419109

https://www.goodreads.com/quotes/13727351-faqs-what-is-the-cheapest-day-to-buy-southwest-airlines

https://metalarea.org/forum/index.php?showtopic=419105

https://airlinesflight.zohodesk.com/portal/en/kb/articles/discount-how-to-get-discounts-on-alaska-flights

https://w.atwiki.jp/sadfasdf23/pages/20.html

https://metalarea.org/forum/index.php?showtopic=419103

https://metalarea.org/forum/index.php?showtopic=419099