Of particular interest arer the labels with intermediate frequency
  (between 1 and 99 occurrences). I separated those into a file 
  .labels-rare.dic.  
  
    8cc8o 8ccoe 8o8orm 8oHccoe 8oHoeo 8oHor 8oeoro 8oero 8orcco8o
    Hoccorom Hoecc8 Horomo Poro cPccor ccPoeo cccHoe cccocHco cccor8o
    cccoro8 cccoroe ccoHoro ccoccro ccoer ccoerom o8r oHcc8occcHoe
    oHcc8oe oHcccc8o oHcccco oHccccor oHccco8o oHccco8or oHcccor
    oHcco8oer oHcco8or oHccocc8o oHccocco oHccooro oHccoror oHccr
    oHco8occcHco oHco8oer oHcoeo oHcoeor oHcoeroe oHcooe8o oHcooeo
    oHcoor oHcoroe oHcororor oHo8oe oHo8or oHo8oro oHoHo oHoHoe
    oHocHco oHocco oHoccor oHoe8oe oHoe8or oHoecc8 oHoecc8o oHoeccoe8o
    oHoeo8 oHoeo8o oHoeoe oHoeoeo oHoeok oHoeom oHoeor oHoeoroe
    oHoeoror oHoer oHoero oHom8om oHomoHom oHorcccHo oHorcco8
    oHorcco8o oHorccok oHorccor oHorco oHoroe8o oHorok oHorom oHoror
    oHororo oHroe oPccco8o oPcccor oPcco8oo oPccor oPccorom oPoeror
    oPorom occc8oe8om occo8o8o occoro oecPco oecccccco oeorom oeoror
    ooPcco oorcccor oorom oroe8 ororcco8om ororoeo qHoe qoHcro rccoor
    ro8or ro8ororo roPoe roe8ok roeP roeccror roeoe roeoer roer roero
    rorccor roroeo roromr rororo rr

  I thought of removing those labels that were superstrings of others
  in the same set, e.g. removing "oHoecc8o" since there is already 
  "oHoecc8". Here is a (rather convoluted) recipe to do that:
  
    cp -p .labels-rare.dic .labs
    @ i = 0
    while ( $i < 4 )
      @ i = $i + 1
      cat .labs \
        | enum-proper-substrings \
        | sort | uniq \
        > .subs.$i
      bool 1.2 .labs .subs.$i \
        > .subs-oc.$i
      if ( -z .subs-oc.$i ) break
      cat .labs \
        | fgrep -v -f .subs-oc.$i \
        > .prop.$i
      cat .subs-oc.$i >> .prop.$i
      cat .prop.$i \
        | sort | uniq \
        > .labs
    end
    
  Here is what it would remove:
      
    bool 1-2 .labels-rare.dic .labs
    
    Hoccorom ccoerom oHcc8occcHoe oHccccor oHccco8or oHcoeor oHo8oro
    oHoHoe oHoccor oHoecc8 oHoecc8o oHoeo8o oHoeoeo oHoeoroe oHoeoror
    oHoero oHorcco8o oHoroe8o oHororo oPccorom oPorom ororoeo ro8ororo
    roeoer roero

  But it seems that those labels are intersting on their own, and
  in some cases much larger than the relevant substrings. So I decided
  to leave them in. 
  
  We should also look at the "rarest" labels (with less than 25 occurrences):
  
    8o8orm 8oHccoe 8oHoeo 8oero 8orcco8o Hoccorom cPccor ccPoeo
    cccor8o cccoro8 ccoccro ccoerom o8r oHcc8occcHoe oHcccc8o oHccccor
    oHccco8or oHcco8oer oHccocc8o oHccooro oHccoror oHco8occcHco
    oHco8oer oHcoeor oHcoeroe oHcooe8o oHcooeo oHcoor oHcoroe
    oHcororor oHo8oe oHo8or oHo8oro oHoHoe oHocHco oHoccor oHoeccoe8o
    oHoeo8 oHoeo8o oHoeoeo oHoeok oHoeom oHoeoroe oHoeoror oHoero
    oHom8om oHorcccHo oHorcco8 oHorcco8o oHorccok oHorccor oHorco
    oHoroe8o oHorok oHroe oPccco8o oPcccor oPcco8oo oPccorom oPoeror
    oPorom occc8oe8om occo8o8o oecPco oecccccco oorcccor ororcco8om
    qHoe qoHcro rccoor ro8or ro8ororo roPoe roe8ok roeP roeccror
    roeoer rorccor roromr

  Now let's find all occurrences of these rare labels in the parags text:

    cat .parags-j-ecc.evt \
      | enum-word-locations .labels-rare.dic \
      | sort -b +2 -3n \
      > .label-rare-occurrences.idx
  
    cat .parags-j-ecc.evt \
      | enum-word-locations .labels-rarest.dic \
      | sort -b +2 -3n \
      > .label-rarest-occurrences.idx

  Let's tabulate their frequencies per page:

    foreach f ( '' -rare -rarest )
      cat .label${f}-occurrences.idx \
        | gawk '/./ { print $1 }' \
        | sed -e 's/\..*>/>/g' \
        | sort | uniq -c | expand \
        | compute-freqs \
        | sort +0 -1nr \
        > .label${f}-refs-by-panel.frq
    end
    
    --- .label-rare-refs-by-panel.frq ------------------------
         93 0.030 <f58r>
         78 0.025 <f113v>
         63 0.020 <f104v>
         60 0.019 <f115r>
         60 0.019 <f86v6>
         57 0.018 <f86v5>
         55 0.017 <f106v>
         53 0.017 <f113r>
         51 0.016 <f116r>
         50 0.016 <f108r>
         49 0.016 <f104r>
         49 0.016 <f105v>
         48 0.015 <f107r>
         44 0.014 <f108v>
         42 0.013 <f106r>
         41 0.013 <f107v>
         40 0.013 <f112r>
         39 0.012 <f103v>
         39 0.012 <f85r1>
         37 0.012 <f115v>
         36 0.011 <f111v>
         36 0.011 <f80v>
         35 0.011 <f114r>
         35 0.011 <f76r>
         35 0.011 <f99v>
         34 0.011 <f103r>
         34 0.011 <f111r>
         34 0.011 <f80r>
         33 0.010 <f79r>
         30 0.010 <f105r>
         28 0.009 <f78v>
         27 0.009 <f66r>
         26 0.008 <f76v>
         25 0.008 <f112v>
         25 0.008 <f79v>
         24 0.008 <f114v>
         24 0.008 <f39v>
         24 0.008 <f40r>
         24 0.008 <f84r>
         23 0.007 <f101r1>
         23 0.007 <f78r>
         22 0.007 <f39r>
         22 0.007 <f75v>
         21 0.007 <f102v2>
         21 0.007 <f77r>
         20 0.006 <f50r>
         20 0.006 <f70r2>
         20 0.006 <f75r>
         19 0.006 <f93r>
         18 0.006 <f82r>
         18 0.006 <f94v>
         17 0.005 <f46v>
         17 0.005 <f48v>
         17 0.005 <f55r>
         16 0.005 <f66v>
         16 0.005 <f94r>
         15 0.005 <f100v>
         15 0.005 <f43r>
         15 0.005 <f47v>
         15 0.005 <f77v>
         15 0.005 <f82v>
         15 0.005 <f89r2>
         15 0.005 <f9v>
         14 0.004 <f102r2>
         14 0.004 <f14v>
         14 0.004 <f1v>
         14 0.004 <f23v>
         14 0.004 <f33r>
         14 0.004 <f55v>
         14 0.004 <f81v>
         14 0.004 <f83r>
         13 0.004 <f34v>
         13 0.004 <f81r>
         13 0.004 <f87v>
         13 0.004 <f88v>
         13 0.004 <f8r>
         12 0.004 <f100r>
         12 0.004 <f101v1>
         12 0.004 <f16v>
         12 0.004 <f1r>
         12 0.004 <f22r>
         12 0.004 <f23r>
         12 0.004 <f2r>
         12 0.004 <f3r>
         12 0.004 <f45r>
         12 0.004 <f54r>
         12 0.004 <f56r>
         12 0.004 <f83v>
         12 0.004 <f84v>
         12 0.004 <f86v3>
         12 0.004 <f8v>
         12 0.004 <f90v1>
         12 0.004 <f95v1>
         12 0.004 <f95v2>
         12 0.004 <f99r>
         11 0.003 <f31v>
         11 0.003 <f36r>
         11 0.003 <f40v>
         11 0.003 <f44r>
         11 0.003 <f49r>
         11 0.003 <f87r>
         11 0.003 <f88r>
         11 0.003 <f9r>
         10 0.003 <f19v>
         10 0.003 <f46r>
         10 0.003 <f48r>
         10 0.003 <f52r>
         10 0.003 <f54v>
         10 0.003 <f86v4>
         10 0.003 <f93v>
         10 0.003 <f96r>
          9 0.003 <f13r>
          9 0.003 <f15v>
          9 0.003 <f16r>
          9 0.003 <f17v>
          9 0.003 <f24r>
          9 0.003 <f27r>
          9 0.003 <f29r>
          9 0.003 <f34r>
          9 0.003 <f51v>
          9 0.003 <f95r2>
          8 0.003 <f101v2>
          8 0.003 <f102v1>
          8 0.003 <f21v>
          8 0.003 <f22v>
          8 0.003 <f24v>
          8 0.003 <f35r>
          8 0.003 <f35v>
          8 0.003 <f37r>
          8 0.003 <f42v>
          8 0.003 <f43v>
          8 0.003 <f56v>
          8 0.003 <f57r>
          7 0.002 <f19r>
          7 0.002 <f30v>
          7 0.002 <f41v>
          7 0.002 <f42r>
          7 0.002 <f45v>
          7 0.002 <f6v>
          7 0.002 <f7v>
          7 0.002 <f89v1>
          7 0.002 <f89v2>
          6 0.002 <f10r>
          6 0.002 <f11v>
          6 0.002 <f13v>
          6 0.002 <f15r>
          6 0.002 <f17r>
          6 0.002 <f20r>
          6 0.002 <f20v>
          6 0.002 <f26v>
          6 0.002 <f32v>
          6 0.002 <f33v>
          6 0.002 <f3v>
          6 0.002 <f52v>
          6 0.002 <f67r2>
          6 0.002 <f6r>
          6 0.002 <f90r1>
          6 0.002 <f90r2>
          6 0.002 <f90v2>
          6 0.002 <f95r1>
          6 0.002 <f96v>
          5 0.002 <f102r1>
          5 0.002 <f11r>
          5 0.002 <f18v>
          5 0.002 <f21r>
          5 0.002 <f25r>
          5 0.002 <f25v>
          5 0.002 <f26r>
          5 0.002 <f2v>
          5 0.002 <f30r>
          5 0.002 <f31r>
          5 0.002 <f32r>
          5 0.002 <f36v>
          5 0.002 <f53r>
          5 0.002 <f53v>
          5 0.002 <f5r>
          5 0.002 <f5v>
          5 0.002 <f69r>
          5 0.002 <f7r>
          4 0.001 <f14r>
          4 0.001 <f27v>
          4 0.001 <f28r>
          4 0.001 <f28v>
          4 0.001 <f29v>
          4 0.001 <f37v>
          4 0.001 <f38r>
          4 0.001 <f44v>
          4 0.001 <f47r>
          4 0.001 <f4r>
          4 0.001 <f50v>
          4 0.001 <f51r>
          4 0.001 <f68v2>
          4 0.001 <f89r1>
          3 0.001 <f10v>
          3 0.001 <f68r2>
          3 0.001 <f68v3>
          2 0.001 <f38v>
          1 0.000 <f18r>
          1 0.000 <f41r>
          1 0.000 <f4v>
          1 0.000 <f65v>
          1 0.000 <f67r1>
    ----------------------------------------------------------
    
    --- .label-rarest-refs-by-panel.frq ------------------------
         28 0.041 <f58r>
         18 0.026 <f113v>
         15 0.022 <f115r>
         13 0.019 <f113r>
         13 0.019 <f66r>
         12 0.017 <f86v5>
         12 0.017 <f99v>
         11 0.016 <f105v>
         10 0.014 <f106v>
         10 0.014 <f116r>
         10 0.014 <f78r>
          9 0.013 <f108r>
          9 0.013 <f85r1>
          9 0.013 <f86v6>
          8 0.012 <f102v2>
          8 0.012 <f103r>
          8 0.012 <f105r>
          8 0.012 <f106r>
          8 0.012 <f107r>
          8 0.012 <f46v>
          8 0.012 <f76r>
          7 0.010 <f104v>
          7 0.010 <f111r>
          7 0.010 <f112r>
          7 0.010 <f84r>
          7 0.010 <f9v>
          6 0.009 <f101r1>
          6 0.009 <f103v>
          6 0.009 <f107v>
          6 0.009 <f108v>
          6 0.009 <f114r>
          6 0.009 <f78v>
          6 0.009 <f80r>
          6 0.009 <f93r>
          5 0.007 <f102r2>
          5 0.007 <f104r>
          5 0.007 <f111v>
          5 0.007 <f114v>
          5 0.007 <f14v>
          5 0.007 <f1v>
          5 0.007 <f23r>
          5 0.007 <f24v>
          5 0.007 <f3r>
          5 0.007 <f45r>
          5 0.007 <f52r>
          5 0.007 <f87r>
          5 0.007 <f8v>
          5 0.007 <f95v2>
          4 0.006 <f100r>
          4 0.006 <f100v>
          4 0.006 <f112v>
          4 0.006 <f13v>
          4 0.006 <f22r>
          4 0.006 <f32v>
          4 0.006 <f33r>
          4 0.006 <f34v>
          4 0.006 <f39r>
          4 0.006 <f51v>
          4 0.006 <f54v>
          4 0.006 <f55v>
          4 0.006 <f6v>
          4 0.006 <f75v>
          4 0.006 <f77r>
          4 0.006 <f77v>
          4 0.006 <f80v>
          4 0.006 <f81v>
          4 0.006 <f86v3>
          4 0.006 <f87v>
          4 0.006 <f88v>
          4 0.006 <f89r2>
          4 0.006 <f90r1>
          4 0.006 <f95v1>
          4 0.006 <f99r>
          3 0.004 <f101v2>
          3 0.004 <f102v1>
          3 0.004 <f11v>
          3 0.004 <f16v>
          3 0.004 <f17v>
          3 0.004 <f19r>
          3 0.004 <f23v>
          3 0.004 <f2r>
          3 0.004 <f30v>
          3 0.004 <f34r>
          3 0.004 <f35r>
          3 0.004 <f37r>
          3 0.004 <f39v>
          3 0.004 <f42r>
          3 0.004 <f47v>
          3 0.004 <f50r>
          3 0.004 <f51r>
          3 0.004 <f57r>
          3 0.004 <f66v>
          3 0.004 <f69r>
          3 0.004 <f79r>
          3 0.004 <f79v>
          3 0.004 <f84v>
          3 0.004 <f86v4>
          3 0.004 <f89v1>
          3 0.004 <f89v2>
          3 0.004 <f90r2>
          2 0.003 <f101v1>
          2 0.003 <f10v>
          2 0.003 <f13r>
          2 0.003 <f14r>
          2 0.003 <f16r>
          2 0.003 <f17r>
          2 0.003 <f18v>
          2 0.003 <f1r>
          2 0.003 <f20r>
          2 0.003 <f22v>
          2 0.003 <f26v>
          2 0.003 <f28r>
          2 0.003 <f30r>
          2 0.003 <f31r>
          2 0.003 <f31v>
          2 0.003 <f35v>
          2 0.003 <f36r>
          2 0.003 <f3v>
          2 0.003 <f40r>
          2 0.003 <f42v>
          2 0.003 <f43r>
          2 0.003 <f45v>
          2 0.003 <f47r>
          2 0.003 <f49r>
          2 0.003 <f4r>
          2 0.003 <f52v>
          2 0.003 <f53r>
          2 0.003 <f54r>
          2 0.003 <f55r>
          2 0.003 <f56r>
          2 0.003 <f5v>
          2 0.003 <f70r2>
          2 0.003 <f75r>
          2 0.003 <f7v>
          2 0.003 <f81r>
          2 0.003 <f83v>
          2 0.003 <f89r1>
          2 0.003 <f8r>
          2 0.003 <f90v1>
          2 0.003 <f90v2>
          2 0.003 <f93v>
          2 0.003 <f94r>
          2 0.003 <f95r2>
          2 0.003 <f96r>
          2 0.003 <f96v>
          2 0.003 <f9r>
          1 0.001 <f115v>
          1 0.001 <f11r>
          1 0.001 <f15r>
          1 0.001 <f15v>
          1 0.001 <f19v>
          1 0.001 <f21r>
          1 0.001 <f21v>
          1 0.001 <f25r>
          1 0.001 <f26r>
          1 0.001 <f27r>
          1 0.001 <f27v>
          1 0.001 <f28v>
          1 0.001 <f29v>
          1 0.001 <f2v>
          1 0.001 <f33v>
          1 0.001 <f37v>
          1 0.001 <f43v>
          1 0.001 <f44r>
          1 0.001 <f46r>
          1 0.001 <f48r>
          1 0.001 <f48v>
          1 0.001 <f53v>
          1 0.001 <f67r2>
          1 0.001 <f68v2>
          1 0.001 <f76v>
          1 0.001 <f82r>
          1 0.001 <f82v>
          1 0.001 <f83r>
          1 0.001 <f88r>
          1 0.001 <f94v>
    ------------------------------------------------------------

  Let's compute the density of label references per page (number
  of references divided by number of text characters in page):
    
    foreach f ( '' -rare -rarest )
      cat .label${f}-refs-by-panel.frq \
        | sort +2 -3 \
        > .foo
      join \
          -a 1 -e 00 \
          -j1 3 -j2 1 \
          -o0,1.1,1.2,2.2 \
          .foo .panels.nchars \
        > .bar${f}
      cat .bar${f} \
        | gawk '/./ {printf "%-8s %5d %5.3f %5d\n", $1, $2, $3, int(1000*$2/$4 + 0.5)}' \
        | sort -b +3 -4nr \
        > .label${f}-refs-by-panel.rfrq
    end

    --- .label-refs-by-panel.rfrq ------------------------
    <f40r>     146 0.005   348
    <f58r>     546 0.020   294
    <f99v>     178 0.006   293
    <f95v2>     69 0.003   273
    <f113v>    636 0.023   269
    <f94r>      99 0.004   268
    <f86v5>    436 0.016   267
    <f55r>     136 0.005   261
    <f95r2>     97 0.004   261
    <f39v>     152 0.006   256
    <f86v6>    563 0.020   252
    <f70r2>    106 0.004   249
    <f23v>      95 0.003   242
    <f23r>     106 0.004   240
    <f86v3>    131 0.005   234
    <f33r>      76 0.003   229
    <f55v>     100 0.004   224
    <f69r>      37 0.001   224
    <f94v>     105 0.004   224
    <f107v>    491 0.018   223
    <f86v4>     45 0.002   223
    <f107r>    511 0.019   219
    <f50r>     104 0.004   218
    <f100v>     87 0.003   215
    <f105v>    395 0.014   215
    <f36r>      58 0.002   215
    <f9v>       79 0.003   215
    <f106r>    482 0.017   213
    <f19v>      75 0.003   213
    <f106v>    475 0.017   211
    ...        ... .....   ...
    <f7r>       30 0.001    89
    <f32v>      31 0.001    87
    <f4v>       35 0.001    87
    <f5r>       22 0.001    85
    <f89r1>     53 0.002    84
    <f68v2>     19 0.001    82
    <f30r>      38 0.001    80
    <f26r>      33 0.001    76
    <f25v>      19 0.001    73
    <f41r>      30 0.001    54
    <f65v>      11 0.000    49
    <f27v>      12 0.000    39
    ------------------------------------------------------
  
    --- .label-rare-refs-by-panel.rfrq ------------------------
    <f99v>      35 0.011    58
    <f40r>      24 0.008    57
    <f58r>      93 0.030    50
    <f86v4>     10 0.003    50
    <f70r2>     20 0.006    47
    <f95v2>     12 0.004    47
    <f14v>      14 0.004    44
    <f94r>      16 0.005    43
    <f33r>      14 0.004    42
    <f50r>      20 0.006    42
    <f36r>      11 0.003    41
    <f9v>       15 0.005    41
    <f39v>      24 0.008    40
    <f47v>      15 0.005    38
    <f94v>      18 0.006    38
    <f100v>     15 0.005    37
    <f23v>      14 0.004    36
    <f67r2>      6 0.002    36
    <f1v>       14 0.004    35
    <f86v5>     57 0.018    35
    <f16v>      12 0.004    34
    <f113v>     78 0.025    33
    <f55r>      17 0.005    33
    <f46v>      17 0.005    32
    <f15v>       9 0.003    31
    <f45r>      12 0.004    31
    <f52r>      10 0.003    31
    <f55v>      14 0.004    31
    <f21v>       8 0.003    30
    <f39r>      22 0.007    30
    ...        ... .....   ...
    <f38v>       2 0.001     8
    <f50v>       4 0.001     8
    <f51r>       4 0.001     8
    <f83r>      14 0.004     8
    <f89v2>      7 0.002     8
    <f84v>      12 0.004     7
    <f67r1>      1 0.000     6
    <f89r1>      4 0.001     6
    <f65v>       1 0.000     4
    <f18r>       1 0.000     2
    <f41r>       1 0.000     2
    <f4v>        1 0.000     2
    -----------------------------------------------------------

    --- .label-rarest-refs-by-panel.rfrq ------------------------
    <f95v2>      5 0.007    20
    <f99v>      12 0.017    20
    <f9v>        7 0.010    19
    <f69r>       3 0.004    18
    <f14v>       5 0.007    16
    <f46v>       8 0.012    15
    <f52r>       5 0.007    15
    <f58r>      28 0.041    15
    <f86v4>      3 0.004    15
    <f90r2>      3 0.004    15
    <f11v>       3 0.004    14
    <f13v>       4 0.006    14
    <f1v>        5 0.007    13
    <f45r>       5 0.007    13
    <f24v>       5 0.007    12
    <f33r>       4 0.006    12
    <f102v2>     8 0.012    11
    <f23r>       5 0.007    11
    <f32v>       4 0.006    11
    <f90r1>      4 0.006    11
    <f100v>      4 0.006    10
    <f51v>       4 0.006    10
    <f87r>       5 0.007    10
    <f19r>       3 0.004     9
    <f30v>       3 0.004     9
    <f3r>        5 0.007     9
    <f54v>       4 0.006     9
    <f55v>       4 0.006     9
    <f5v>        2 0.003     9
    <f87v>       4 0.006     9
    ...        ... .....   ...
    <f80v>       4 0.006     2
    <f81r>       2 0.003     2
    <f84v>       3 0.004     2
    <f88r>       1 0.001     2
    <f94v>       1 0.001     2
    <f43v>       1 0.001     1
    <f46r>       1 0.001     1
    <f75r>       2 0.003     1
    <f82r>       1 0.001     1
    <f82v>       1 0.001     1
    <f83r>       1 0.001     1
    <f83v>       2 0.003     1
    <f115v>      1 0.001     0
    <f76v>       1 0.001     0
    -------------------------------------------------------------