URL tags for search engine identifaction

What engine they belong t oo

[peter1az]

Hi

I notice people using tags at the end of there url like this

index.htm?ref=mv

the?ref=mv tag is to show that the traffic is coming from a specific search engine named miva

We know that mv at the end of a tag can mean enything , but i checked them up and are consistant in what they put at there tags

Now my question is ,do any of you where this tag

index.htm?ref=adu-c

is comming from ,What search engine has these tree letters
in it adu-c

thanks