
in a letter to David Croal Thomson (1907), as cited in: The Brothers Maris (James – Matthew – William), ed. Charles Holme; text: D.C. Thomson https://ia800204.us.archive.org/1/items/cu31924016812756/cu31924016812756.pdf; publishers, Offices of 'The Studio', London - Paris, 1907, p. BMxvii