Jak posortować taką tablicę:

[PHP] pobierz, plaintext 
 
Array
(
    [0] => Array
        (
            [0] => PO317XU
            [1] => PO789YV
        )
 
    [1] => Array
        (
            [0] => BGN2024
            [1] => BGN2080
        )
 
    [2] => Array
        (
            [0] => BGN2025
            [1] => BGN2070
        )
 
    [3] => Array
        (
            [0] => FG0251C
            [1] => FG94523
        )
 
    [4] => Array
        (
            [0] => DLWCF84
            [1] => DLW53WP
        )
 
    [5] => Array
        (
            [0] => RZ7381K
            [1] => RZ3553P
        )
 
    [6] => Array
        (
            [0] => RZ9613K
            [1] => RZ3703P
        )
 
)
 
[PHP] pobierz, plaintext 

Według pierwszej wartości?

Doszedłem do takiego momentu i nie mogę dalej dopisać tych drugich wartości:

[PHP] pobierz, plaintext 
Array
(
    [0] => Array
        (
            [0] => BGN2024
        )
 
    [1] => Array
        (
            [0] => BGN2025
        )
 
    [2] => Array
        (
            [0] => DLWCF84
        )
 
    [3] => Array
        (
            [0] => FG0251C
        )
 
    [4] => Array
        (
            [0] => PO317XU
        )
 
    [5] => Array
        (
            [0] => RZ7381K
        )
 
    [6] => Array
        (
            [0] => RZ9613K
        )
 
)
[PHP] pobierz, plaintext 

Proszę o pomoc, bo walczę z tym godzinę już.

http://php.net/manual/en/function.usort.php