U.S. booksellers are showing their support for Charlie Hebdo.

This week, the American Booksellers Association announced it was actively seeking copies of the most recent edition of the French satirical newspaper, whose Paris headquarters was recently rampaged by Islamist gunmen. The attack left 12 people dead, including the newspaper’s editor and nine other employees.

“Following the horrific killings of the staff of Charlie Hebdo and others in Paris, many booksellers have reached out to the ABA and the American Booksellers for Free Expression (ABFE) asking how they can stand in solidarity with the magazine and its commitment to free speech,” the association said in a statement. “In response, ABA is actively exploring the logistics of obtaining copies of the upcoming issue of Charlie Hebdo for member stores to carry.”

Copies of the commemorative “Je Suis Charlie” issue are hard to come by. Despite upping the usual print run of 60,000, millions of copies sold out in hours when it hit newsstands on Wednesday, and many of those issues turned up later in online auctions at 100 times the original list price, Time reported.

As it works on obtaining copies of the paper, ABA is asking members to take part in a social media campaign in the interim. In an email to members, CEO Oren Teicher encouraged members to take photos of themselves holding signs reading “Je Suis Charlie” and post them to their social media accounts with the hashtag #JeSuisCharlie—all of which would hopefully encourage others to participate.

“For this to spread as quickly and as widely as possible, it’s critical that booksellers encourage their customers and friends to join in by both posting pictures of themselves and making donations,” the association said. “The hope is that the campaign will grow quickly and will help demonstrate that violence and intimidation cannot stifle debate, discussion, and freedom of expression.”

Booksellers are not alone in their support of Charlie Hebdo. Last week several cartoonist groups came out backing free speech and denouncing the attack on the newspaper known for its provocative political cartoons, many of which offend Muslims because they depict the prophet Mohammed.

“We encourage the world’s press to show their support for free speech by republishing the very cartoons that caused this attack,” Cartoonists Rights Network International said in a statement. “We are in awe at the courage of the French cartoonists at Charlie Hebdo.”