As far as I know, the primary reference is Sebert & Hugoniot, 'Etude Des Effects De La Poudre' (Paris). 1882. It appears in some form (perhaps not by name) in most discussion of internal ballistics however since it's an important part of understanding efficiency, more so in the 20th century with the takeover of bottleneck cartridges. It's less interesting for most artillery (no shoulder, generally), although still important - I remember seeing a discussion of Sebert's work in an early 20th century Journal of The United States Artillery but I don't remember the exact year. Probably around 1905 or so.
