Part of the reason for this is that the actual regional cultures run by different names and many papers are not in English. To complicate things even more, the regional cultures themselves run by different names in different nations. Like one of the main Pre-G�va cultures of the area between Hungary, Slovakia, Romania and Ukraine was Suciu de Sus. You find in Hungarian way more hits if you search for Felsőszőcs, which is the same place, just the Hungarian version.
And in English you have different names for the Pottery: G�va style, channelled pottery, pottery with channels, fluted ware, fluted pottery, pottery with cannelures, sometimes even Protovillanova or Hallstatt style, especially in the oldest articles.
Maps:
https://www.researchgate.net/public...te_Bronze_Age_and_Early_Iron_Age_Transylvania
Among experts its being widely known and its appeareance marks the beginning of a new epoch in the Balkans, because it marks the Late Bronze to Iron Age transition. Its being used to relatively date finds in stratigraphies even. And among others in the book of Kristian Kristiansen its core group of G�va being considered Proto-Thracian. A view held up by a minority, but a solid one with many researchers in the last decades.
Here another point of view on the subject, note that Fluted Ware horizon being the same as channelled ware/pottery or cannelure pottery etc. Just different names for the same phenomenon. In Bulgaria they prefer Fluted ware, for whatever reason:
So at first Encrusted Pottery (which fled Tumulus culture and Channelled Ware from Pannonia) and Brnjica (which fled Channelled Ware) made their appearance. This already shows what happened: It was a multiple chain reaction event, caused by first Tumulus culture, then Channelled Ware, expanding in Pannonia and the Balkans. This also caused parts of the Sea Peoples migrations and Protovillanova in Italy being a related branch within Urnfield. In the next stage:
They mention migration but tend to interpret it otherwise (pots no people preference). But ancient DNA already shows that E-V13 wasn't there before, but appeared in the main Channelled Ware successor, which is Psenichevo. So its ancient DNA to decide whether the massive and radical change caused by Channelled Ware as a cultural complex, which encompassed much more than just the ceramic, was a demic diffusion, even replacement event or not. But since we have many samples from the Bronze Age without E-V13, but plenty of afterwards, things are going in the right direction.
Already if looking at the massive change of the culture in all Channelled Ware affected areas, there can be no doubt it was a migration, from the archaeological point of view, but the question remains which extent. Like did a minority come in, without replacing a lot of the locals, and just spread the culture then. Or was it really a fairly massive replacement event? That's up to ancient DNA to solve this once and for all. Just like they did it with Bell Beakers.
I don't know, but considering their style and the incoming steppe push, Bulgaria/Lower Danube is likely, after they had come down from the Western steppe from MCW/Catacomb before. That's what the results of Central-Eastern European genetic profiles (according to the authors) appearing with the MBA-LBA transition in the Aegean might suggest. We need to wait for the results from those paper, like there are so many other results we know about which need forever to get published.