Citation:
Zhang C, Evans NJ, Liu T, Wu J-W, Wang K, Liu H-L, Zhu F-Y, Ren Z-Y, Dewangan L K, Lee CW, et al. ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - IV. Radio recombination lines and evolution of star formation efficiencies. \mnras. 2022;510:4998-5008.