"Ernst Haeckel - Britannica Concise" (biography), Encyclopædia Britannica Concise, 2006, Concise. Pàgina web Britannica.com: CBritannica-HaeckelArxivat 2006-11-11 a Wayback Machine.
Biography of Ernst Heinrich Haeckel, 1834-1919 (article), Missouri Association for Creation, Inc., based on 1911 Britannica, webpage: Gennet-HaeckelArxivat 2006-10-17 a Wayback Machine.: life, career & beliefs.
Michael K. Richardson. 1998. "Haeckel's embryos continued." Science 281:1289, quoted in NaturalScience.com webpage Re: Ontogeny and phylogenyArxivat 2006-11-14 a Wayback Machine.: A Letter from Richard Bassetti; Editor's note.
The Controversy over Evolution in Biology Textbooks (Texas, Textbooks and Evolution), Dr. Raymond G. Bohlin (President), Probe Ministries, 2003, Probe.org webpage: ProbeOrg-Textbook-Controversy: mentions Haeckel drawings.
"Ernst Haeckel - Britannica Concise" (biography), Encyclopædia Britannica Concise, 2006, Concise. Pàgina web Britannica.com: CBritannica-HaeckelArxivat 2006-11-11 a Wayback Machine.
Michael K. Richardson. 1998. "Haeckel's embryos continued." Science 281:1289, quoted in NaturalScience.com webpage Re: Ontogeny and phylogenyArxivat 2006-11-14 a Wayback Machine.: A Letter from Richard Bassetti; Editor's note.
Haeckel's embryos (of drawings, with detailed quotes by Haeckel & others), Tony Britain, 2001, AntiEvolution.org webpage: AE-mythsArxivat 2007-08-09 a Wayback Machine..
Biography of Ernst Heinrich Haeckel, 1834-1919 (article), Missouri Association for Creation, Inc., based on 1911 Britannica, webpage: Gennet-HaeckelArxivat 2006-10-17 a Wayback Machine.: life, career & beliefs.