You've been redirected here from http://www.sfu.ca/~yzhang/linux . The vi quick reference sheet originally created by yhang is unfortunately no longer available at this site. There are a number of mirrors of this document still available online, I'll list some here and can add others. Please email me at mstanger (at) sfu (dot) ca if you know of another mirror and I'll add it to the list. This initial list was compiled from a simple Google search for "vi Quick Reference yzhang", and that is probably the best way to find a currently available copy
As of the time of this writing, here are active mirrors of the document