Field, George B., Blackman, Eric G., and Keto, Eric R. 2011. "Does external pressure explain recent results for molecular clouds?." Monthly Notices of the Royal Astronomical Society 416:710-714. https://doi.org/10.1111/j.1365-2966.2011.19091.x
The recent paper by Heyer et al. indicates that observations of size, linewidth and column density of interstellar clouds do not agree with simple virial equilibrium (SVE) as a balance between gravitational and kinetic energies in the sense that the clouds either have too much kinetic energy or too little mass to be bound. This may be explained by violation of SVE as suggested by Dobbs et al., by observational underestimation of the masses as suggested by Heyer et al. or by an external pressure acting as an additional confining force as suggested earlier by Heyer et al. The data of Heyer et al. cannot be explained with a single value for the external pressure, but if different clouds
