I looking for literature  for $\mathbb{P}_k$ bubble enriched for finite elements. 
Literature for $\mathbb{P}_k$ bubble enriched for finite elements
finite element
In our paper Finite element decomposition ... flow equations -- see my webpage http://janheiland.de/publications.html for a link to the postprint -- we have touched on such bubble enriched Finite Element spaces.The sources we based on wereV. Girault and P.-A. Raviart, Finite Element Methods for Navier-Stokes Equations. Springer-Verlag. Berlin (1986)C. Bernardi and G. Raugel, Analysis of some finite elements for the Stokes problem. Math. Comput. 44(1985) 7179.