Supervised models are trained on a variety of data features related to the structure, semantics and syntax of the text. The idea behind is to effectively explore the latent connections between citing context and sentences in the reference paper.
La Quatra, M., Cagliero, L., & Baralis, E. (2019). Poli2Sum@CL-SciSumm-19: Identify, Classify, and Summarize Cited Text Spans by means of Ensembles of Supervised Models. In 4th Joint Workshop on Bibliometric-enhanced Information Retrieval and Natural Language Processing for Digital Libraries (BIRNDL 2019) @ SIGIR 2019 (Vol. 2414, pp. 233–246). http://ceur-ws.org/Vol-2414/paper24.pdf