I revisited films that portray human experiences, the passing of life. The Apu Trilogy, 'Pather Panchali' especially, for the way it portrays childhood and family. That was very important.
We watched The Battle of Algiers with the crew for the journalistic camera, the way Pontecorvo creates the sense of reality from a subjective point of view, but also this sort of immediate chaos.
For the car sequence, we showed Godard's Weekend. Not for the realism, but to show how a single shot can sustain tension and character interaction over a long period.
2001 and Tarkovsky's Solaris are the two films that come to mind. They are films that I admire greatly and were an influence.