New Existence and Nonexistence Results for Strong External Difference   Families
  In this paper, we use character-theoretic techniques to give new nonexistence results for $(n,m,k,\lambda)$-strong external difference families (SEDFs). We also use cyclotomic classes to give two new classes of SEDFs with $m=2$. 
Jingjun Bao, Lijun Ji, Ruizhong Wei, Yong Zhang
math.CO