For PSG articles before 2017, please go to the old website (

The search mechanism on this old website is poor and readers might prefer to use Google’s advanced search facilities (see below). (These advanced Google search facilities can, if desired, also be used on the current PSG site ).

To use the advanced Google search facilities friendly interface:

  • In your browser, initialise a Google search with some text in the regular way.
  • In the menu near the top select ‘settings’, then ‘advanced search’.
  • In the site box on the ninth row enter: (or for the new site).
  • Then enter data in various other boxes as appropriate to set up the search filters. (Unfortunately, you cannot set up a custom time range but see below how to get around this!).
  • Press the ‘Advanced Search’ button.
  • The regular search interface then appears this time with the text to be searched and various filters in operator format.
  • You can now use a second set of filters by opening the ‘tools’ menu. In particular you can select a custom time range.

There are various tutorials on the web (for example: to understand how to make best use of the advanced facilities.