Kingdom of Poland or Lithuanian coin

What is the main difference between Kingdom of Poland Półgrosz litewski coin (https://en.numista.com/catalogue/pieces130413.html) and halfgroat of Lithuania (https://en.numista.com/catalogue/pieces35049.html)?
I have few of these coins and identification is a bit challenging, so any help would be nice. I also would like to know a good book mainly reference book regarding both of these coins.

...Does there have to be a difference at all? I personally suspect that those two are ultimately differently catalogued versions of the same type.

This is the same type ......
You can send me the pictures of Your Lithuanian coins in pm, I'l try to help You with identification.
Or You can ask for the help in our group https://www.facebook.com/halfgroats/
About the difference of Polish and Lithuanian monetary systems of 15-16 centuries You can read in https://en.numista.com/forum/topic49601.html

P.S. I will send You the book from ebay tomorrow. Today all the postage offices were closed - the second day of Easter is Holiday in Lithuania.

Thank you for helping me. I'll prepare some photos this week.

Pólgrosz Litewski literally means Lithuanian Half Groat in Polish. So based on the name it's the same thing.

This is the first problematic coin, it is either Polish coin or Lithuanian coin. Measurements are: 1.1 g; 20.0 mm / 0.6 mm.

I have bought this as a Lithuanian coin from Gdansk.
So any help would be nice and also the criterion how you identified it.

This is the Lithuanian coin, with the White Knight (Vytis in Lithuanian) , Lithuanian Coat of Arms on obverse. Today it's still our Coat of Arms https://en.wikipedia.org/wiki/Coat_of_arms_of_Lithuania so it's the best way to recognize the Lithuanian coin.
About Your coin. Lithuanian half-groat of Sigismund the Old, dated 1512. Gothic legend, 3 Knight and 3 Eagle by our book. Minted in Vilnius, silver 375 https://en.numista.com/catalogue/pieces35049.html
40D in our book. https://www.ebay.com/itm/264403704971


You can watch for all the coinage of this ruler on https://fortresscatalogue.com/coin_types.php?type=king&king_code=100.000000

Great, thank you. The fortresscatalogue -page is also great and after having the book, I think I will manage somehow.

Attention please : there are too much mistakes in fortresskatalog part about the coins of Grand Duchy Lithuanian. Their Polish coins description is much much better.