A coalition of art-world heavyweights is backing a new campaign to re-install Beatrix Ruf as the director of Amsterdam’s Stedelijk Museum. Ruf, a widely influential curator known for her ability to spot rising talent, resigned abruptly last October after allegations of conflict of interest emerged in the Dutch media.

A full-page advertisement was published in Saturday’s edition of the Amsterdam newspaper Het Parool demanding the museum “call Ruf back.” The advertisement was signed by artists Wade Guyton, Richard Serra, Marina Abramović, Laurie Anderson, Joep van Lieshout and Seth Price; the architect Rem Koolhaas, and the composer Phillip Glass among others.

The ad directed readers to an online petition, which has so far received more than 315 signatures—and the list is growing fast. Artists including Haim Steinbach, Jordan Wolfson, and Jon Rafman have signed on, along with dealers David Zwirner, Jeanne Greenberg Rohatyn, and Rodolphe Janssen. So far, there are comparatively fewer museum directors and curators on the list, although Suzanne Cotter, the director of the Musée d’Art Moderne du Grand-Duc Jean in Luxembourg, and Stefan Kalmár, the director of London’s Institute of Contemporary Arts, have added their names.

The petition simply states that the German-born curator should be re-instated “because of her artistic vision.”

According to the Dutch media, the effort was spearheaded by the Amsterdam gallery owner Rob Malasch, and the advertisement was paid for by an anonymous supporter. Five individuals, including Arno Verkade, the director of Christie’s Netherlands, and Rotterdam-based design dealers Saskia Copper and Aad Krol, have since told NRC they did not knowingly sign the petition.

One of the signatories who did confirm, the Greek collector Dakis Joannou, told artnet News that he added his name to the petition—which he received from the dealer Eva Presenhuber—because Ruf is “a person who I have known for years and have no reason to doubt her integrity and competency.” A selection of others named in the advertisement and online petition did not immediately respond to a request for comment.

Ruf was criticized after it emerged that she continued to run an art advisory service while she was serving as the museum’s director. She also came under fire for a lack of transparency in the museum’s part-gift, part-purchase of works from the German collector Thomas Borgmann.

A representative from the Stedelijk Museum said the institution is aware of the advertisement and appreciates “that those who signed the petition feel so involved.” The spokeswoman declined to comment further until two independent investigations spurred by Ruf’s departure are complete.

The municipality of Amsterdam is currently investigating whether Ruf’s pay was in line with that of Dutch civil servants and whether the institution remained in compliance with Dutch cultural governance code. The results are due to be published in April.