Lembo, L. J.; H. Helm; D. L. Huestis «Measurement of vibrational frequencies of the H3 molecule using two-step photoionization». The Journal of Chemical Physics, 90, 10, 1989, pàg. 5299. Bibcode: 1989JChPh..90.5299L. DOI: 10.1063/1.456434. ISSN: 00219606.
Lembo, L. J.; H. Helm; D. L. Huestis «Measurement of vibrational frequencies of the H3 molecule using two-step photoionization». The Journal of Chemical Physics, 90, 10, 1989, pàg. 5299. Bibcode: 1989JChPh..90.5299L. DOI: 10.1063/1.456434. ISSN: 00219606.
Lembo, L. J.; H. Helm; D. L. Huestis «Measurement of vibrational frequencies of the H3 molecule using two-step photoionization». The Journal of Chemical Physics, 90, 10, 1989, pàg. 5299. Bibcode: 1989JChPh..90.5299L. DOI: 10.1063/1.456434. ISSN: 00219606.