implementations of maximum likelihood refinement

[HEFFRON at UCRAC1.UCR.EDU]

I would like to try the maximum likelihood refinement technique, but would
like some advice about what implementation is recommended.  I have seen some
mention of maximum likelihood being run using x-plor, but have not seen a
sample input file to run this.  Does anyone have one they would be willing
to post?  Or is it available in a tutorial directory for x-plor 3.851?  (I'm
currently running x-plor 3.843.)  

Or, is refmac the implementation that most people are using?  I'm not an
experienced CCP4 user, which is why I asked about x-plor first, but if
refmac is highly recommended, then I'll just have to learn...

Or, is there another program for maximum likelihood that I should consider
getting?  I'd appreciate hearing all recommendations.
 
                           Thanks in advance,
                           Susan Heffron

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Biochemistry Dept.                      |          heffron at ucrac1.ucr.edu
University of California, Riverside     |          phone: (909) 787-4196
Riverside, CA 92521                     |          fax:   (909) 787-3590
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