What is the difference between P#8a, P#8b and P#8c? [gelöst]

I have a 5 Pula Note, but I can't see whether it is an 8a, 8b, or 8c. What is the difference between these catalog entries?

I'm assuming it is signatures, but they are not listed.

Hello again. Yes, signatures. This should help.  http://www.banknote.ws/COLLECTION/countries/AFR/BOT/BOT0008.htm

The Numista banknote page should explain that.

Many thanks, mine is an 8c.

I'll scan it and add it as an example.