Are there any rules of thumb that dictate the noun+noun construction, that is, without an intervening preposition? E.g. why
projet recherche, responsable qualité, débat marathon, la stratégie Mitterrand, les années Poutine, etc.
and not
projet de recherche, responsable de qualité, la stratégie de Mitterrand
and so on?
There are several articles such as
https://www.linguistiquefrancaise.org/articles/cmlf/pdf/2008/01/cmlf08132.pdf
but I am looking something more elementary.