| https://www.startupnetworks.co.uk/topic/923-ways-to-call-lufthansa-customer-service-by-phone-chat-and-email-options-methods-explained/ |
| https://papers.ssrn.com/sol3/papers.cfm?abstract_id=5298884 |
| https://www.startupnetworks.co.uk/topic/968-how-to-easily-reach-united-airlines-customer-service-number-2025-updated-guide/ |
