Apfel, C. M., Takács, B., Fountoulakis, M., Stieger, M., & Keck, W. (1999). Use of Genomics To Identify Bacterial Undecaprenyl Pyrophosphate Synthetase: Cloning, Expression, and Characterization of the Essential uppS Gene. American Society for Microbiology.

Apfel, Christian M., Béla Takács, Michael Fountoulakis, Martin Stieger, and Wolfgang Keck. Use of Genomics To Identify Bacterial Undecaprenyl Pyrophosphate Synthetase: Cloning, Expression, and Characterization of the Essential UppS Gene. American Society for Microbiology, 1999.

Apfel, Christian M., et al. Use of Genomics To Identify Bacterial Undecaprenyl Pyrophosphate Synthetase: Cloning, Expression, and Characterization of the Essential UppS Gene. American Society for Microbiology, 1999.