Foreign-gas pressure broadening and shift of ammonia transition lines in the ν₂ vibrational bands, Baldacchini, G., Bizzarri A., Nencini Luca, Sorge V., Buffa G., and Tarrini O. , Journal of Quantitative Spectroscopy and Radiative Transfer, 1990///, Volume 43, p.371 - 380, (1990)