Public Papers of the President

I was recently looking for Public Papers of the President for the Nixon administration. A quick check at GPOaccess and NARA suggested that the Weekly Compilation of Presidential Documents are searchable from 1993 and browsable from 2001, and the Public Papers are available (search and browse) from 1991. I thought I was out of luck and then stumbled upon the American Presidency Project - there you can search or view by month/year public papers from the Hoover administration onward, as well as The Messages and Papers of the Presidents 1789-1913!!! Perhaps everyone knows this (I'm rusty on reference) but I was amazed and delighted!