Zend youtube api order types

I use zend youtube api for get video form youtube for my project. I have a questions - which type of开发者_高级运维 orders exists. Example $yt->setOrder(''viewCount'); - 'viewCount' one of type of order. Please help. I want know all types of order, like 'date', 'modifiedd'... etc.

You can find them on the Youtube API reference pages:

http://code.google.com/apis/youtube/2.0/reference.html#orderbysp

EDIT: It doesn't look like you can order by 'updated', (unless its undocumented), so the closest match is probably to sort on published instead.