Lijuan Fu, Ying Qing, Richard Parnas, Yingying Liu, Changjun Liu, Bin Liang,Wei Jiang, Houfang Lu, Purification of Biodiesel by Bubbling CO2 to React with 1,8-Diazabicyclo[5.4.0]undec-7-ene and Glycerol, Journal of Biobased Materials and Bioenergy, 2018, 12, 3: 259-265(7) DOI: 10.1166/jbmb.2018.1763