  We work out a quantum-theoretic model in complex Hilbert space of a recently
performed test on co-occurrencies of two concepts and their combination in
retrieval processes on specific corpuses of documents. The test violated the
Clauser-Horne-Shimony-Holt version of the Bell inequalities ('CHSH
inequality'), thus indicating the presence of entanglement between the combined
concepts. We make use of a recently elaborated 'entanglement scheme' and
represent the collected data in the tensor product of Hilbert spaces of the
individual concepts, showing that the identified violation is due to the
occurrence of a strong form of entanglement, involving both states and
measurements and reflecting the meaning connection between the component
concepts. These results provide a significant confirmation of the presence of
quantum structures in corpuses of documents, like it is the case for the
entanglement identified in human cognition.
