How to link static libraries --- in .pro file settings?

Hi, all:

How can I setup the .pro file to make sure I can link with those static libraries?

For instance, in my case, my compilation gave me the following error message
Code:

cannot find -lutils
In fact, there is a
Code:

libutils.a
right there.

What's in my .pro file is like:
Code:

LIBS += -L/usr/local/lib \ -L../utils/bin/debug \ -lutils \
Well, is
Code:

-lutils \
the right way to link static libraries?

How to link those static libraries produced by my own code?

Cheers
JIA