Wollmer, Erik, and Sandra Klein. “Development and Validation of a Robust and Efficient HPLC Method for the Simultaneous Quantification of Levodopa, Carbidopa, Benserazide and Entacapone in Complex Matrices”. Journal of Pharmacy & Pharmaceutical Sciences, vol. 20, July 2017, pp. 258-69, doi:10.18433/J3K923.