correction to: fe3o4@sio2-ptms-guanidine-sa nanoparticles as an effective and reusable catalyst for the synthesis of n-substituted pyrroles

The article “fe3o4@sio2-ptms-guanidine-sa nanoparticles as an effective and reusable catalyst for the synthesis of n‑substituted pyrroles”, written by hedieh rostami · lotfi shiri, was originally published electronically on the publisher’s internet portal (currently springerlink) on 21 2020 with open access. with the author(s)’ decision to step back from open choice, the copyright of the article changed on 2020 to © iranian chemical society 2020, part of springer nature 2020, and the article is forthwith distributed under the terms of copyright.