https://www.medicinenet.com/doxycycline_vs_tetracycline/article.htm#what_is_the_difference_between_doxycycline_and_tetracycline - Biology bibliographies - in Harvard style

In-text: (Bynum and Bynum, 2007)

Your Bibliography: Bynum, W. and Bynum, H., 2007. Dictionary of medical biography. Westport, Conn.: Greenwood Press.

In-text: (List of Sulfonamides + Uses, Types & Side Effects - Drugs.com, 2018)

Your Bibliography: Drugs.com. 2018. List of Sulfonamides + Uses, Types & Side Effects - Drugs.com. [online] Available at: <https://www.drugs.com/drug-class/sulfonamides.html> [Accessed 1 July 2018].

In-text: (Doxycycline vs. Tetracycline: Side Effects & Dosage for Antibiotics, 2018)

Your Bibliography: MedicineNet. 2018. Doxycycline vs. Tetracycline: Side Effects & Dosage for Antibiotics. [online] Available at: <https://www.medicinenet.com/doxycycline_vs_tetracycline/article.htm#what_is_the_difference_between_doxycycline_and_tetracycline> [Accessed 3 July 2018].

In-text: (Omudhome Ogbru, 2018)

Your Bibliography: Omudhome Ogbru, P., 2018. Sulfonamides: Drug Facts, Side Effects and Dosing. [online] MedicineNet. Available at: <https://www.medicinenet.com/sulfonamides-oral/article.htm#what_are_the_side_effects_of_sulfonamides?> [Accessed 1 July 2018].