  In this paper new Steiner systems $S(2,6,121)$, $S(2,6,126)$ are introduced.
Also some non-existence results for line lengths $7..9$ are presented. There is
no solid proof that presented algorithm is exhaustive or correct, but it
produces same results on already known difference families for line lengths
$3..5$. Due to calculation-based approach this paper probably won't be
published, but will be submitted to arxiv as it contains some new results
