Unit with Long spear etc contacted flank or rear

Does such a unit still get the long spear etc advantage, specifically cancelling chargers' impetus bonus if they are mounted?  I have found in the rules where it states the depth bonus does not apply, but can't find this, even though Bing tells me it doesn't.

What Bing said:
In Basic Impetus 2.0, the rules for units equipped with long spears and similar weapons indeed change when it comes to flank or rear charges. Specifically, the benefits these units typically enjoy in frontal engagements do not apply if they are attacked from the side or rear. This reflects the historical difficulty of defending against such attacks.

But I can't find a reference to the actual rule.

Hey SoY

I have read over the section on Impetus bonus again and can find no mention of Front only for Long Spear , so as the rules are written, long spear etc works against flank and rear charges also .

Phil

yes, I confirm that Long Spear works also if caught on fank or rear. Of course large Units may suffer other disvantages in this situation, but it is assumed that enough troops can turn and point their spears in sufficient number to cancel the impetus.

Thanks