Translating an informal mathematical argument into a proof which conforms to the norms of the mathematical community in which it is situated is a non-trivial task. Here we discuss several types of products, other than the initial informal argument and its direct formalisation, which we observed students generating in a master's level analysis course in the United States during their attempts to formalise a researcher-generated informal argument. We refer to these as formalisation artefacts and discuss the various roles they play relative to students' attempts to formalise informal arguments.