8. A method according to claim 1 , wherein generating said species identifier comprises determining the species of the said individual mention of the subcellular entity by looking for species words which are close to the individual mention of a subcellular entity in the biomedical text document.
1. A method of using a data-processing apparatus, having a processor, to normalize an individual mention of a subcellular entity within a biomedical text document, the method comprising using the data-processing apparatus to carry out: inputting said individual mention of a subcellular entity; selecting a group of identifiers of subcellular entities, said subcellular entities being referred to in biomedical text with the same character string and being from different species, each of said species being a taxonomic group of organisms which can interbreed; generating, using said processor, a species identifier that identifies the species of said individual mention of a subcellular entity from the context of said mention of a subcellular entity; selecting an identifier from said group of identifiers, taking into account the species identifier that identifies the species of said individual mention of a subcellular entity; and outputting said identifier to provide a normalized reference to said subcellular entity.