Partial parallelisrms Uhat admit a collineation group that fixes one spread \(\Sigma\), fixes a line of it and acts sharply two-transitive on the remaining lines of \(\Sigma\) are completely classified.
Citation
Norman L.Johnson, Rolando Pomareda. Partial Parallelisms With Sharply Two-Transitive Skew Spreads[J], Ars Combinatoria, Volume 070. 275-287. .