The foundation of any modern research is the theoretical base built by researchers who previously studied or currently studying a selected field.

The research topic we have chosen — Particles in Russian, English, and German — indicates the need to study the theory of parts of speech in a contrastive-typological aspect. In this regard, the classical studies of parts of speech in compared languages ​​have become many reference points.

Since approaches to the study of particles vary significantly from researcher to researcher, from one research paradigm to the other, there is a need for constant updating of the list of references and constant work and interaction with particle researchers. At the moment, we have proposed a “basic” list of sources, which can serve as a starting point for the study of particles in compared languages. This list is available on the cloud data website of a research project and is available for editing. However, taking into account the complexity of the issue under study, this list is not finite and is subject to constant updating.