I am looking for a comprehensive list of Internet-banking software
developer companies with main headquarters in the following countries:

Bulgaria 
Croatia 
Czech Republic 
Hungary 
Latvia 
Lithuania 
Poland 
Romania 
Slovak Republic 
Slovenia 

I expect 2-4 company names per country. Important: I am not looking
for companies with branches, development centers or sales offices in
those countries, but for companies having their main HQ there!

I need the following information per company:

HQ country, Company name, web address, 2-3 references (?biggest? referenced banks)

Thanks!

I believe you will do better if you post a separate question for each
country. When they are bundled together, this presents a daunting task
that many Researchers may not find attractive for the price offered.

Thanks for the advice, i will do that.