Duplicating Rotations

How can I work out the different sets of rotations that are equivalent… i.e.

glrotatef(0, 1, 0, 0);
glrotatef(90, 0, 1, 0);
glrotatef(0, 0, 0, 1);

is the same as

glrotatef(90, 1, 0, 0);
glrotatef(90, 0, 1, 0);
glrotatef(90, 0, 0, 1);

cheers

gav

Doh check the matrix!..