Multilicense `debian/copyright` file

[Aliaksei Sheshka <sheshkaoss@gmail.com>]

Hi debian-devel list!

Please help me to write a proper `debian/copyright` file.

Original COPYING file says:

Several parties hold copyright to various parts of IRRToolSet.  One or more

of the following licenses may apply to the code contained within this

distribution.

1. USC (and occasionally USC/IBM) license

.....

2. RIPE NCC license

....

3. GNU General Public License version 2

...

What should put in the `debian/copyright` then ?