Two years of solar wind and pickup ion measurements at comet 67P/Churyumov–Gerasimenko - Goldstein, R; Burch, JL; Mokashi, P; Mandt, K; Carr, C; Eriksson, A; Glassmeier, K-H; Henri, P; Nilsson, H; Rubin, M; Tzou, C-Y (Monthly Notices of the Royal Astronomical Society, 2017)