How to delete web links from references in Gost style?

Question

I need to remove web links like DOI and Pubmed from litterature references produced in Gost style. What functions and lines of code are responsible for that?

Reference looks like:

Weyn, B. Determination of tumour prognosis based on angiogenesis-related vascular patterns measured by fractal and syntactic structure analysis / B. Weyn, W. A. Tjalma, P. Vermeylen et al . // Clin Oncol (RColl Radiol) . — 2004. — Vol . 16 № 4. — P. 307–316 . — http : //www . ncbi . nlm . nih . gov/ ,pubmed/15214656 .

I need to delete http links.

%%
%% This is file `gost780s.bst',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% gost.dtx  (with options: `bst,sort')
%% 
%% This file may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%   http://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
%% 
%% This file has the LPPL maintenance status "maintained".
%% Maintained by Igor A. Kotelnikov.
%% Current version: 2012.02.02
%% 
%% Please, send bug report via e-mail:
%%   kia999 at mail dot ru <Igor Kotelnikov>
%% or
%%   polyama at yahoo dot com <Maksym Polyakov>
%% 



%%
%% This bibstyle attempts to format bibliography according to
%% GOST 7.80-2000 for bibliographic records.

Here a part of code:

FUNCTION {format.url}
{ url empty$
    { "" }
       {
        "\BibUrl{ " url * "}" *
        urldate empty$
         { "" }
          { " (" bbl.urldate * ": " * urldate * ")" * }
       if$ *
     }
  if$
}

FUNCTION {format.annote}
{ annote empty$
    { "" }
{ after.sentence 'output.state :=
  "\BibAnnote{" annote add.period$ * "}" *
}
  if$
}

%%FUNCTION {format.isbn}
{
  %%isbn empty$
   %% { "" }
   %% { "ISBN:~\href{http://isbndb.com/search-all.html?kw=" isbn *
   %%   "}{" * isbn * "}" *
   %% }
  %%if$
}

FUNCTION {add.doi} { }

FUNCTION {add.medium} { }


FUNCTION {output.eprint.url}
{
  %%  format.url output
}