`   == References to GNU C-Graph == Long before I wrote the proposed article ``GNU C-Graph``, I included references under the articles Convolution theorem and Convolution for the benefit of students and their professors teaching and learning about convolution. These references were removed by  and . Notwithstanding my belief that GNU C-Graph meets the WP:Notability criteria,  pointed out ``external links aren't required to be WP notable, just relevant``.  Most reasonable people would agree that removing the reference to the only software that easily demonstrates the convolution theorem would be a disservice to the public. The text of the references reads:  Under Convolution#External_links: *GNU C-Graph, a free software package for visualizing the convolution theorem, and displaying signals with their spectral plots.  Under Convolution_theorem#Additional_resources: *GNU C-Graph, a free software package for demonstrating the convolution theorem, and displaying signals with their spectral plots.  No doubt some WP:AGF administrator will recognise the educational value and reinstate the references for the benefit of the public.  `