FWIW, I waited longer (30 to 60 seconds) now, and it did load (though was too laggy to interact with). It would be too painful to profile/debug at these speeds, but if you will be looking into further optimization, a few options that come to mind are: a textual representation (an article name and lists of referenced and referencing ones), a 2D interactive graph (those made with D3.js tend to be not so laggy), or a static graph -- a picture. Pretty sure an interactive 3D graph can also be made to work, but likely that would require to find out what is causing the lags.