Access script from a namespace

Hello I just came across a situation: I'd like to have access to a class i wrote, which I didn't included in any namespace, from the script ThirdPersonUserControl (from standard assets), which is in the namespace UnityStandardAssets.Characters.ThirdPerson. The problem is the class name is unknown, as if i was missing a "using". So I was wondering if there is a default namespace for the scripts created in unity, or if there is another problem in what i did, that i'm not aware of? I didn't find topics answering it. Thanks!