Nonexistence of Strong External Difference Families in Abelian Groups of Order Being Product of At Most Three Primes

Let $v$ be a product of at most three not necessarily distinct primes. We prove that there exists no strong external difference family with more than two subsets in abelian group $G$ of order $v$, except possibly when $G=C_p^3$ and $p$ is a prime greater than $3\times {10}^{12}$.