Veryovkin, Igor V., Calaway, Wallis F., Moore, Jerry F., Pellin, Michael J., Lewllen, John W., Li, Yuelin, Milton, Stephen V., King, Bruce V., Petravic, Mladen. Elsevier Science BV; 2004. A new horizon in secondary neutral mass spectrometry: post-ionization using a VUV free electron laser.