The scientific study of any object requires research in documentary sources. Whether these are private or public archives, legacies left to museums or other heritage institutions, the search for information is a necessity for understanding the life of the object, from its creation to its study in situ. Today, many types of documentary source are available on line, in particular on the website of the French Ministry of Culture. These sources are available to all and easy to consult. The example presented here, concerning the study of religious furnishings of the 19th and 20th centuries, the production of which increased considerably during these centuries, are the pages taken from the catalogues of several manufacturers of these church furnishings, today accessible on line.