Szilágyi Pál: How to define relevant markets in the tourism sector?. Nr. 2017/17.
One of the sectors that gets a lot of attention recently is the travel industry. This is mainly due to the emergence of online travel agencies, like Booking.com or Expedia and the increase of their power. Most of the issues that are relevant to the discussion are not new in competition law, most-favoured nation clauses, two-sided platforms, oligopolistic interdependence, etc. are all well-known issues. The nature of the distribution network and models is, however, undergoing a lot of change and at some points, the approach of competition authorities seems to be wrong. It is widely known that a key issue in competition assessments is the definition of the relevant market. This is a make or break issue for well-known reasons.
 See e.g. Carlton, Dennis W.: Market Definition: Use and Abuse. Competition Policy International, 3/1. 3., Baker, Jonathan B.: Market Definition: An Analytical Overview. Antitrust Law Journal, 74/1. 129., Townley, Christopher: The Relevant Market: An Acceptable Limit to Competition Analysis? SSRN eLibrary. Link: http://ssrn.com/paper=1894815.