pip freeze без зависимостей установленных пакетов

When I do pip freeze I get the packages I've explicitly installed plus those packages that are dependencies of those packages.

For example:

$ pip install fabric
...
$ pip freeze
Fabric==1.0.1
paramiko==1.7.6
pycrypto==2.3

Ok fine but then I move to install this requirements.txt on another environment with pip install I'd get the same result with the last 2 lines removed.

So my question is: how I can I create the most simplified requirements.txt where all calculable dependencies are not shown?