Constructing vector-valued Siegel modular forms from scalar-valued   Siegel modular forms
  This paper gives a simple method for constructing vector-valued Siegel modular forms from scalar-valued ones. The method is efficient in producing the siblings of Delta, the smallest weight cusp forms that appear in low degrees. It also shows the strong relations between these modular forms of different genera. We illustrate this by a number of examples. 
Fabien Cl\'ery and Gerard van der Geer
math.AG math.NT