diff --git a/lib/unicodesymbols b/lib/unicodesymbols
index 416d9f0d62..820209c868 100644
--- a/lib/unicodesymbols
+++ b/lib/unicodesymbols
@@ -839,8 +839,8 @@
 0x03bf "\\textgreek{o}"           "textgreek" "" # GREEK SMALL LETTER OMICRON
 0x03c0 "\\textgreek{p}"           "textgreek" "mathalpha" "\\pi" "" # GREEK SMALL LETTER PI
 0x03c1 "\\textgreek{r}"           "textgreek" "mathalpha" "\\rho" "" # GREEK SMALL LETTER RHO
-0x03c2 "\\textgreek{c}"           "textgreek" "force,mathalpha" "\\varsigma" "" # GREEK SMALL LETTER FINAL SIGMA
-0x03c3 "\\textgreek{sv}"          "textgreek" "force,mathalpha" "\\sigma" "" # GREEK SMALL LETTER SIGMA
+0x03c2 "\\textgreek{c}"           "textgreek" "force=iso8859-7,mathalpha" "\\varsigma" "" # GREEK SMALL LETTER FINAL SIGMA
+0x03c3 "\\textgreek{sv}"          "textgreek" "force=iso8859-7,mathalpha" "\\sigma" "" # GREEK SMALL LETTER SIGMA
 0x03c4 "\\textgreek{t}"           "textgreek" "mathalpha" "\\tau" "" # GREEK SMALL LETTER TAU
 0x03c5 "\\textgreek{u}"           "textgreek" "mathalpha" "\\upsilon" "" # GREEK SMALL LETTER UPSILON
 0x03c6 "\\textgreek{f}"           "textgreek" "mathalpha" "\\varphi" "" # GREEK SMALL LETTER PHI