Stavangerflint bowl

Hello
Can anyone give me any further information about this bowl. I think it is a Inger Waage design from my investigations but am new to this. I would like to know anything anyone can tell me about it. It's a lovely bowl the colours are very striking. It's marked on the bottom Stavangerflint Norway 57 - 24 (not 100% sure the numbers are correct so I have taken a photo of the base). there is also a black and silver oval shaped label stuck to the inside of the bowl. The measurements are 9.5cm x 7.5cm across the top and 4cm deep at its narrowest point 5cm deep at the widest point the flat base is 3cm diameter. I said there would be a photo of the base but I had some trouble inserting the photo so gave up at one the underside is black with the flat base unfinished apart from the marking. I would particularly like to know the date and possibly the value of this piece.
Thanks a million

I recently picked up a small Stavangerflint dish by Inger Waage, and I believe yours is another example of her work.
There's a useful website about her http://stavangerflint.gratisnettside.no/?mid=194# and if you scroll a third of the way down you'll see a rectangular dish with the same fish design as your bowl.


Here's mine - a little tobacco pipe stand decorated with a bird.





As for value, they seem to be selling on ebay for around £15-£20 depending on subject matter. And it's nice that yours still has the original label, while mine is unmarked.