1. “Effect of methyl-δ-valerolactams on the quality of ɛ-caprolactam”;Romero;Ind. Eng. Chem. Res.,2004
2. “New progress and the production process for caprolactam”;Yang;Synth. Technol. Appl.,1996
3. “Discussion on impurity in caprolactam”;Peng;China Synth. Fiber Ind.,1999
4. “Qualitative analysis of impurities in caprolactam produced by SINA process”;Yu;J. Instrum. Anal.,2004
5. “New caprolactam process”;Giuffre;Hydrocarbon Process.,1973