Helen (Greek: Ἑλένη) is a play by Euripides based on a variant legend in which the real Helen never reached Troy but was taken to Egypt by the God Hermes, where she is rescued by Menelaus.
Free online texts
Internet Archive: Euripides I. Iphigeneia at Aulis, Rhesus, Hecuba, The daughters of Troy, Helen. Bilingual Loeb edition, translated by Arthur Sanders Way. Multiple formats.
Internet Classics Archive: Helen, translated by E.P. Coleridge. HTML and TXT formats.
Loebulus: L009 - Euripides -- Euripides I: Iphigenia at Aulis. Rhesus. Hecuba. The Daughters of Troy. Helen. Greek and English parallel text. Loeb edition, PDF format.
Poetry in Translation: Helen, translated by George Theodoridis, Multiple formats.
University of Adelaide (Internet Archive): Helen, translated by E.P. Coleridge. Multiple formats.
History of Ancient Greece: Euripides at War, podcast by Ryan Stitt.
Sententiae Antiquae: Paris Donned a Menelaos Disguise to Convince Helen to Go To Troy! 7 October 2016.
Wikipedia: Helen (play)
The Great Conversation: Further reading at Tom's Learning Notes
Herodotus: The Histories - gives a version of the story that Helen never reached Troy, but took refuge in Egypt.
Thucydides: History of the Peloponnesian War - discounted Helen's role in the origins of the Trojan War.
Euripides: Iphigenia in Tauris- a play with a similar escape theme.
A.E. Haigh: The Tragic Drama of the Greeks (1896).
Ancient Greek resources: Learn to read Greek classics in the original.
Bloom's Western Canon: Helen is listed.