You could also do this yourself:
1. Google broglie matter wave
2. click ref 6
3. click ref 1 (1923) -- no joy. click ref 2. (the 1927 one, then )
Aha ! HAL is the repository.
4. Click Search -- Louis de broglie -- advanced search -- search field author full name -- bingo
Dutch expression: a child can do the laundry. English 'equivalent': a piece of cake. French ? sais pas