“Arete and Bia in Euripides’ Herakles” by H. H. O. Chalk, Journal of Hellenic Studies 82 (1962)

Chalk’s article is a classic work of scholarship discussing the role of heroic virtue (arete) and bia (strength) in Euripides’s Heracles. The article aims to refute the idea—once influential—that Heracles exhibits signs of madness before Hera drives him mad.

“Unity and Meaning of Euripides’ Heracles” by J. C. Kamerbeek, Mnemosyne 19 (1966)

Kamerbeek’s articles discusses the themes and dramatic structure of Euripides’ Heracles, providing a good introductory overview for readers.

Heracles and Euripidean Tragedy by T. Papadopoulou, Cambridge University Press (2005)

Papadopoulou’s book explores the ambivalent depiction of Heracles in traditional Greek mythology and in Euripides’s Heracles.

Euripides: Heracles by E. Griffiths, Bristol Classical Press (2006)

Griffiths offers a useful overview of the play and various interpretations of it. The book is part of a series of handbooks on Greek and Roman tragedy.