Looking for info about a drinking glass.

[twade]

I have a small, white drinking glass with a drawing of a duckling
inbetween a bar and a tree. It also contains a little poem:

D is for duckling
With eyes big and round
He floats on the water
And swims sitting down

I know there is a cow glass of similar design. I cannot find anything
else about these glasses. I'd like to know more about who made them,
when, and how I can find more to buy.

Any help would be greatly appreciated. Thanks!