NATO Defense College has published an analytical article on the concept of “hybridity” in the context of warfare.
The beginning of the hybrid war in the East Ukraine was the impulse for understanding “hybridity” in the Western community, writes the author, Michael Rühle:

“Russia’s apparently seamless and effective blending of political, diplomatic, economic, electronic and military tools in order to annex Crimea and support separatists in the Donbas seemed to herald a new era of hybrid warfare: a revisionist power was using both old and new means to undermine and, eventually, tear down a post-Cold War order it considered unfair and unfavourable”.

There are separate chapters in the publication that focus on the challenges and methods of deterring hybrid threats.

The text is available in English: Deterring hybrid threats: the need for a more rational debate