G337.342-0.119 (The "Pebble"): A cold, dense, high-mass molecular cloud with unusually large line widths and a candidate high-mass star cluster progenitor

- Jackson, James M.; Contreras, Yanett; Rathborne, Jill M.; Whitaker, J. Scott; Guzman, Andrés; Stephens, Ian W.; Sanhueza, Patricio; Longmore, Steven; Zhang, Qizhou; Allingham, David