^Chollet D, Künstner P (June 1992). "Fast systematic approach for the determination of drugs in biological fluids by fully automated high-performance liquid chromatography with on-line solid-phase extraction and automated cartridge exchange. Application to cebaracetam in human urine". Journal of Chromatography. 577 (2): 335–40. doi:10.1016/0378-4347(92)80255-o. PMID1400764.