The shape of the S-curve in resource utilization of project management is well established for its persistence. Adrian Bejan (a mechanical engineering professor at Duke University), has extended the applicability of S-curve as a logistic function to the spread of ideas, technology etc. I am thinking that because of its wide utility, this function and the shape it represents, can also show the evolving boundary of the dynamic of teaming process in a project. PM BOK, does not list S-curve as a subject index or as a key word though it references the term on p. 213-214, in its treatment of cost management plan, as cost aggregation.

The mathematical idea of S-curve is credited to Pierre Verhulst (1804-1849) who was mainly interested in the study of growth of the population of Belgium, and based on later analyses, he was very close to the actual evolution of that population. Today, that function is typically referred to as logistic function (with sigmoid function being a special case).  

Ali