Sooke 2015: "The foundation therefore concludes that Leonardo was responsible for the face and hands of the woman in the Isleworth picture, while an inferior artist must have painted the clumsy landscape in the background". Sooke, Alastair (16 February 2015). "The Isleworth Mona Lisa: A second Leonardo masterpiece?". BBC. Retrieved 10 June 2020.
Sooke 2015, noting that "Syson does not accept that scientific evidence can conclusively settle debates over the authenticity of pictures such as the Isleworth Mona Lisa". Sooke, Alastair (16 February 2015). "The Isleworth Mona Lisa: A second Leonardo masterpiece?". BBC. Retrieved 10 June 2020.
Sooke 2015: "Like Eyre and Pulitzer before them, the current owners of the Isleworth painting are convinced that it is in part by Leonardo. Yet, like Eyre and Pulitzer, they are struggling to convince leading scholars. As well as Kemp, other respected Leonardo experts including the German art historian Frank Zollner deny that there is any substance to their claims". Sooke, Alastair (16 February 2015). "The Isleworth Mona Lisa: A second Leonardo masterpiece?". BBC. Retrieved 10 June 2020.
Isaacson 2017, p. 491: "Even as Leonardo was perfecting the Mona Lisa, his followers and some of his students were making copies, perhaps with an occasional helping hand from the master. Some are very good, including those known as the Verono Mona Lisa and the Isleworth Mona Lisa, prompting claims that they may have been painted wholly or mostly by Leonardo, though most academic experts are skeptical". Isaacson, Walter (2017). Leonardo da Vinci (1st ed.). New York City, New York: Simon & Schuster. ISBN978-1501139154.
Hales 2017, p. 252: "'The Mona Lisa is perfectly beautiful...' Blaker wrote to his sister Jane. 'I think there is big money in it.'" Hales, Dianne (2017). Mona Lisa: A life discovered. New York City, New York: Simon & Schuster. ISBN978-1451658972.
Hales 2017, p. 252: "Most agreed that Leonardo may have painted the face and hair while another artist or artists complete the throat, hands, background. Despite these endorsements, all based on 'connoisseurship,' or subjective appraisal, Eyre and his son-in-law never succeeded in establishing the portrait as a genuine Leonardo". Hales, Dianne (2017). Mona Lisa: A life discovered. New York City, New York: Simon & Schuster. ISBN978-1451658972.
The Editors of Encyclopaedia Britannica 2019: "Other copies of the Mona Lisa include the so-called Isleworth Mona Lisa, which some commentators asserted was Leonardo's first version of the famed portrait. The claim was a controversial one, with several leading Leonardo scholars flatly denying it". The Editors of Encyclopaedia Britannica (18 July 2019). "Mona Lisa". Encyclopædia Britannica, inc. Retrieved 10 June 2020.
Cohen 2018: "For the last four decades, a portrait of a woman closely resembling the subject of Leonardo da Vinci's famed Mona Lisa has remained under lock and key in a Swiss vault". Cohen, Jennie (30 August 2018). "Has the Original Mona Lisa Been Found?". history.com. A&E Television Networks. Retrieved 10 June 2020.
Lorenzi 2012: "In 1915 his stepfather John R. Eyre, an art historian, published a book suggesting that Leonardo painted two versions of the Mona Lisa and claiming that at least the bust, the face and the hands of the Isleworth lady were a genuine work by Leonardo Da Vinci –- basically, a prequel to his famous portrait". Lorenzi, Rossella (27 September 2012). "Younger, Happier Mona Lisa: Is It A Da Vinci?". Live Science. Future US. Retrieved 11 June 2020.
The Mona Lisa Foundation: "The purpose of the foundation is to investigate the evidence that Leonardo da Vinci painted two versions of the Mona Lisa portrait and to present the art history, scientific research and comparative studies of the earlier version of the portrait, historically referred to as the 'Isleworth Mona Lisa'". The Mona Lisa Foundation. "Foundation - The Mona Lisa Foundation". The Mona Lisa Foundation. Retrieved 11 June 2020.
Eyre 1923, pp. 34–35. Eyre, John (1923). The Two Mona Lisas: which was Giacondo's picture?: ten direct, distinct, and decisive data in favour of the Isleworth version, and some recent Italian expert opinions on it. London, England: J.M. Ouseley & Son. OCLC19335669.
Eyre 1923, pp. 37–38. Eyre, John (1923). The Two Mona Lisas: which was Giacondo's picture?: ten direct, distinct, and decisive data in favour of the Isleworth version, and some recent Italian expert opinions on it. London, England: J.M. Ouseley & Son. OCLC19335669.
Eyre 1923. Eyre, John (1923). The Two Mona Lisas: which was Giacondo's picture?: ten direct, distinct, and decisive data in favour of the Isleworth version, and some recent Italian expert opinions on it. London, England: J.M. Ouseley & Son. OCLC19335669.
