Where is Oldenburg?
Oldenburg is located in the north of Germany, about 50 km west of Bremen.
There are several maps which describe this better.
Be aware that Universität Oldenburg has two campuses: Campus Wechloy and Campus Haarentor. The conference takes place at Campus Wechloy (Carl von Ossietzky Straße). The line 306 (direction: Universität) is the preferred way to reach the Campus Wechloy from Oldenburg central station.
... by plane
Since Oldenburg does not have its own airport you may book a flight to Bremen, Hamburg, Hannover or Frankfurt (Amsterdam is less convenient). For European visitors we recommend using Bremen's airport since it has flights to many other airports in Europe.
All flight plans are available on the airports' sites:
After arriving on your desired airport you may continue by using the train, airport shuttle or taxi (from Bremen), by car or by bus:
... by train
Oldenburg has a train station with very good connections to Bremen, and from there to many major European cities. Be aware of buying a ticket to Oldenburg in Oldenburg, also written as Oldenburg (Oldb), and not to Oldenburg in Schleswig-Holstein.
... by airport shuttle or taxi (Bremen airport only)
There is a shuttle that picks you up at Bremen airport and drops you off at your hotel in Oldenburg. You will have to make an advance reservation, either by telephone during business hours (9 am - 5 pm local time, ..49-441-811 14), at least a day in advance -- or via a web form. The transfer takes about 50 minutes. You will be picked up at the exit door inside the airport, by someone with a sign that has your name on it. For more information, see Luftibus.
... by bus
Near the Oldenburg train station is a Flixbus station.