[Ger-Poland-Volhynia] Lipjanin Katarina and Dehnik Gnat from Kustrawa (Poland)

[Serhiy Romaniuk]

Dear friends,
I'm looking for information on my grandfather and grandmother. There names are Lipjanin Katarina, she was born october-november 1921 and Dehnik (Dekhnik) Gnat (Hnat), he was born 31 of December 1919.
They both where living in Kustrawa village in Poland. The village is near town Lezajsk and near another, bigger village Bystre. 
Later, after II World war  they immigrated with there parents to USSR (Ukraine). My question is: where can I find papers on them, in what archives or lists? Where could be some written evidences that they where living there, in Kustrawa?  
Please, advise.
Thank you.