CDL netlist format

I have CDL net lists using different ways to connect the substrate pin of a transistor:

Q1 net1 net2 net3 [net4] npn M=1

Q2 net1 net2 net3 npn M=1 $SUB=net4

Q3 net1 net2 net3 net4 npn M=1

Q4 net1 net2 net3 npn area M=1

Which one of the above format is the correct syntax ?

Or do the different tools/versions accept only some of the formats ?

Especially 'Q4' seems to be ambiguous, because "npn" can be an optional substrate node or the model name ?

Thanks

Heinz