Παραπομπή σε μορφή APA (7η εκδ.)

Harpen, N. H. v., & Watkins, S. J. (1930). The electrometric determination of the hydrogen ion concentration in the latex of Hevea brasiliensis and its applicability to technical problems. Varekamp & Co.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Harpen, Nicolaas Hendrik van, και S. J. Watkins. The Electrometric Determination of the Hydrogen Ion Concentration in the Latex of Hevea Brasiliensis and Its Applicability to Technical Problems. Medan: Varekamp & Co, 1930.

Παραπομπή σε μορφή MLA (8th εκδ.)

Harpen, Nicolaas Hendrik van, και S. J. Watkins. The Electrometric Determination of the Hydrogen Ion Concentration in the Latex of Hevea Brasiliensis and Its Applicability to Technical Problems. Varekamp & Co, 1930.