Exploration does still take place, but on an unofficial basis.

It was amazing how much could be accomplished on an unofficial basis.

Regan had discussed it, after all, only with Tim Field, on an unofficial basis.

Nevertheless, relations with Taiwan continued on an unofficial basis.

The messenger was insistent that he must talk to you first on an unofficial basis.

But if you carry on for a few more days on an unofficial basis, that's your business.

Dogs have been associated with the school's sports teams on an unofficial basis since the late nineteenth century.

An England source said: 'Geoff has always been willing to help on an unofficial basis.

I worked with him on an unofficial basis.

The Raider organization does not retire the jersey numbers of former players on an official or unofficial basis.