Cita APA (7a ed.)

Helbing, H. (1891). Modern materia medica: For pharmacists, medical men, and students (2nd enl. ed.). The British & Colonial Druggist.

Cita Chicago Style (17a ed.)

Helbing, H. Modern Materia Medica: For Pharmacists, Medical Men, and Students. 2nd enl. ed. London: The British & Colonial Druggist, 1891.

Cita MLA (8a ed.)

Helbing, H. Modern Materia Medica: For Pharmacists, Medical Men, and Students. 2nd enl. ed. The British & Colonial Druggist, 1891.