The warp and spiral arms of the milky way

Levine, E. S., Blitz, L., Heiles, C., & Weinberg, M. (2008). The warp and spiral arms of the milky way. In Astrophysics and Space Science Proceedings (Vol. 0, pp. 85–90). Springer Science and Business Media B.V. https://doi.org/10.1007/978-0-387-72768-4_12