The attribution and re-attribution work is ongoing. In 2005 four oil paintings previously attributed to Rembrandt's students were reclassified as the work of Rembrandt himself: "Study of an Old Man in Profile" and "Study of an Old Man with a Beard" from a US private collection, "Study of a Weeping Woman", owned by the Detroit Institute of Arts, and "Portrait of an Elderly Woman in a White Bonnet", painted in 1640. The "Old Man Sitting in a Chair" is a further example: in 2014, Professor Ernst van de Wetering offered his view to "The Guardian" that the demotion of the 1652 painting "Old Man Sitting in a Chair" "was a vast mistake...it is a most important painting. The painting needs to be seen in terms of Rembrandt's experimentation". This was highlighted much earlier by Nigel Konstam who studied Rembrandt throughout his career.