https://pressbooks.pub/alloverseasexpertise/chapter/%e2%9f%aaaa%f0%9d%95%8b%e2%84%9d%f0%9d%95%96%e2%84%95%f0%9d%95%95%f0%9d%95%80%e2%84%95%f0%9d%95%98-%e2%9f%abwhat-day-does-american-airlines-drop-prices-2/