Two things stand out in a study of publications that have been written from the perspective of memoria. First, academics with various backgrounds are involved in this field of research: historians, literary historians, music historians, art historians, and church historians and liturgical experts. This is hardly surprising, as memoria touched all kinds of aspects of society and culture.

Many publications, then, testify to a collaboration between scholars who were educated in different fields. But publications also show that researchers often select sources closely related to the discipline in which they have been trained, even if the use of a combination of sources would be better considering the research questions.

In the second place it is striking that (until recently) many researchers were largely focusing on case studies and small-scale projects, and hardly engaged in systematic comparative studies across time and space. As a result, scholars often avoid the question of the representativeness of phenomena.

This situation is largely due to a practical problem. The various types of research materials and the large (larger) number of objects and texts required for quantitative and qualitative broad comparative research are widely dispersed over archives, libraries and museums. Researchers therefore often lack a knowledge of the existence of these materials.

The dispersal of the sources has several causes. The Reformation is one. Many of the written sources and works of art came in the possession of the cities when the monasteries were dissolved around 1580 in the larger part of the area that is currently the Netherlands. Other sources have disappeared, for instance because the conventuals who left the area took them with them.

But also in later periods sources were lost or were taken out of their original contexts. In Utrecht, for instance, a number of floor slabs are currently situated in other churches than the original one, even though that church still exists: eight floor slabs in the Domkerk originate from the Buurkerk, and three floor slabs from the Domkerk have been transferred to the Janskerk. This type of transfers are usually the result of restoration projects that were undertaken in the twentieth century, see for instance: MeMO memorial object ID 2869 and ID 2494. Clearly we cannot assume per se that the medieval institutions where the objects are located today are the institutions of origin.

The dispersal of the sources is therefore problematic, as it hampers the search for the required materials, but also because researchers often need to know in which institution the texts and objects originated to be able to infer their use.