Construction Formulae for Singular Vectors of the Topological N=2   Superconformal Algebra
  The Topological N=2 Superconformal algebra has 29 different types of singular vectors (in complete Verma modules) distinguished by the relative U(1) charge and the BRST-invariance properties of the vector and of the primary on which it is built. Whereas one of these types only exists at level zero, the remaining 28 types exist for general levels and can be constructed already at level 1. In this paper we write down one-to-one mappings between 16 of these types of topological singular vectors and the singular vectors of the Antiperiodic NS algebra. As a result one obtains construction formulae for these 16 types of topological singular vectors using the construction formulae for the NS singular vectors due to Doerrzapf. 
Beatriz Gato-Rivera