Wierzbicka, Anna (1975). Topic, focus, and deep structure. Papers in Linguistics, 8(1/2), 59-87. DOI: 10.1080/08351817509370390

The interpretation of the phenomena associated with the terms “topic” and “focus” which will be proposed here forms a part of a general semantic theory, the main assumption of which is that the semantic representation of an utterance should be its “explication”, i.e. its paraphrase in natural
language which would employ only indefinable expressions. It is claimed that the indefinable expressions be found in any natural language correspond to a universal set of elementary semantic units.