Can't find links to my site(s)

PR4, but search for linking sites turns up empty

[ariet]

Several of my clients have a PR of 4 or higher on Google, but when I search for links to their sites from other sites (link:domain.com) Google says it can't find any links.

How can I have a PR4 and not be able to find links?

In addition, there is one domain in particular that consistently returned a certain set of links, but Google suddenly can't find them anymore. The site that features the links has not changed, though.

[jeremy goodrich]

I believe Google only shows backlinks that are PR 4 and higher in with the link: command.

Try searching for your back links at alltheweb.com or altavista.com sometimes they have a more comprehensive back link list in their results.

[ariet]

Even the sites that are PR4 on Google don't show when I search for backlinks.

However, the searches on the other SEs return a reasonable number of backlinks.

One wonders why Google would not display those backlinks.