Tchernyshyov, Peek & Zasowski (2018) – Kinetic Tomography. II. A Second Method for Mapping the Velocity Field of the Milky Way Interstellar Medium and a Comparison with Spiral Structure Models
van de Hulst, Muller & Oort (1954) – The spiral structure of the outer part of the Galactic System derived from the hydrogen emission at 21 cm wavelength
