APA (7th ed.) Citation

ScienceDirect (Online service), Zeeuw, R. A. d., & Marko, V. (1989). Determination of beta-blockers in biological material. Elsevier.

Chicago Style (17th ed.) Citation

ScienceDirect (Online service), R. A. de Zeeuw, and V. Marko. Determination of Beta-blockers in Biological Material. Amsterdam: Elsevier, 1989.

MLA (9th ed.) Citation

ScienceDirect (Online service), et al. Determination of Beta-blockers in Biological Material. Elsevier, 1989.