Because the Guild approach is based upon the Principles and the concepts of the Core Syllabus which are held to be universal across almost all the arts, any historical source can be used to promote the understanding and applications of those elements.
In general, sources that present as complete a representation of skills will be used. Those being most accessible being preferable. As well, those that allow for the more direct development of key concepts are also preferred. Once the core concepts have been internalised the individual scholar may decide to study more obscure sources.
Individual Chapters, Study Groups or individuals within the Guild may focus their attention on specific manuals, weapons or periods covered by the historical sources as their primary areas of study. As such the common language of the Guild is that of the Principles and the Core Syllabus, rather than specific interpretations of specific manuals and manuscripts. As such as long as interpretation can be shown to apply and the Principles and Core Syllabus, it will be hald to be valid the Guild even if it is different to that applied by other Guild groups.