Spinor Field Realizations of Non-critical $W_{2,s}$ Strings
  In this paper, we construct the nilpotent Becchi-Rouet-Stora-Tyutin($BRST$) charges of spinor non-critical $W_{2,s}$ strings. The cases of $s=3,4$ are discussed in detail, and spinor realization for $s=4$ is given explicitly. The $BRST$ charges are graded. 
Yi-Shi Duan, Yu-Xiao Liu, Li-Jie Zhang