Sibling fights

[MyCatIsAStupidBastard]

Hoping someone can help me out with some advice or point me in the direction of some good books.

My DD is 7 and my DS is 3 (4 in Feb) and can get on really well but at other times fight like billyo. A lot of it comes down to DD either bossing DS around or teasing him. I range from dealing with calmly to shouting (rubbish, I know)

Can anyone give me some tips to keep me calm and help me help my DC.

Sorry this isn't giving many details but the flaming auto spell check on the kindle fire has made this a torture to type out

I'm not sure of any magic answers but will watch with interest as DH and his DB took chunks out of each other and I dread our two DSs following suit.

I have zero tolerance with hitting etc, many, many time outs (and I shout too, don't think anyone can stay cool and calm all the time), with proper apologies to each other.

Thankfully our DS1 (6) is the gentle one and it's DS2 (2) I have to watch, rather than the other way round.

Zero tolerance for hitting, rudeness and bullying. Time out no questions asked. One or both.

Rewards for getting on well.

Thank you both. I think we have both been less than calm which does not help.

Will be much more consistent.

Any good books out there?