diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 94d2a22..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-language: java
-jdk:
-  - openjdk11
diff --git a/build.gradle b/build.gradle
index e8e661b..6f10294 100644
--- a/build.gradle
+++ b/build.gradle
@@ -25,6 +25,7 @@ ext {
 
 apply plugin: 'java-library'
 apply from: rootProject.file('gradle/ide/idea.gradle')
+apply from: rootProject.file('gradle/repositories/maven.gradle')
 apply from: rootProject.file('gradle/compile/java.gradle')
 apply from: rootProject.file('gradle/test/junit5.gradle')
 apply from: rootProject.file('gradle/publishing/publication.gradle')
diff --git a/config/checkstyle/checkstyle.xml b/config/checkstyle/checkstyle.xml
deleted file mode 100644
index 55e59d2..0000000
--- a/config/checkstyle/checkstyle.xml
+++ /dev/null
@@ -1,323 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE module PUBLIC
-        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
-        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
-
-<!-- This is a checkstyle configuration file. For descriptions of
-what the following rules do, please see the checkstyle configuration
-page at http://checkstyle.sourceforge.net/config.html -->
-
-<module name="Checker">
-
-    <module name="FileTabCharacter">
-        <!-- Checks that there are no tab characters in the file.
-        -->
-    </module>
-
-    <module name="NewlineAtEndOfFile">
-        <property name="lineSeparator" value="lf"/>
-    </module>
-
-    <module name="RegexpSingleline">
-        <!-- Checks that FIXME is not used in comments.  TODO is preferred.
-        -->
-        <property name="format" value="((//.*)|(\*.*))FIXME" />
-        <property name="message" value='TODO is preferred to FIXME.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-    </module>
-
-    <module name="RegexpSingleline">
-        <!-- Checks that TODOs are named.  (Actually, just that they are followed
-             by an open paren.)
-        -->
-        <property name="format" value="((//.*)|(\*.*))TODO[^(]" />
-        <property name="message" value='All TODOs should be named.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-    </module>
-
-    <module name="JavadocPackage">
-        <!-- Checks that each Java package has a Javadoc file used for commenting.
-          Only allows a package-info.java, not package.html. -->
-    </module>
-
-    <!-- All Java AST specific tests live under TreeWalker module. -->
-    <module name="TreeWalker">
-
-        <!--
-
-        IMPORT CHECKS
-
-        -->
-
-        <module name="RedundantImport">
-            <!-- Checks for redundant import statements. -->
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="ImportOrder">
-            <!-- Checks for out of order import statements. -->
-
-            <property name="severity" value="warning"/>
-            <property name="groups" value="com.google,android,junit,net,org,java,javax"/>
-            <!-- This ensures that static imports go first. -->
-            <property name="option" value="top"/>
-            <property name="tokens" value="STATIC_IMPORT, IMPORT"/>
-        </module>
-
-        <!--
-
-        JAVADOC CHECKS
-
-        -->
-
-        <!-- Checks for Javadoc comments.                     -->
-        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
-        <module name="JavadocMethod">
-            <property name="scope" value="protected"/>
-            <property name="severity" value="warning"/>
-            <property name="allowMissingJavadoc" value="true"/>
-            <property name="allowMissingParamTags" value="true"/>
-            <property name="allowMissingReturnTag" value="true"/>
-            <property name="allowMissingThrowsTags" value="true"/>
-            <property name="allowThrowsTagsForSubclasses" value="true"/>
-            <property name="allowUndeclaredRTE" value="true"/>
-        </module>
-
-        <module name="JavadocType">
-            <property name="scope" value="protected"/>
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="JavadocStyle">
-            <property name="severity" value="warning"/>
-        </module>
-
-        <!--
-
-        NAMING CHECKS
-
-        -->
-
-        <!-- Item 38 - Adhere to generally accepted naming conventions -->
-
-        <module name="PackageName">
-            <!-- Validates identifiers for package names against the
-              supplied expression. -->
-            <!-- Here the default checkstyle rule restricts package name parts to
-              seven characters, this is not in line with common practice at Google.
-            -->
-            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]{1,})*$"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="TypeNameCheck">
-            <!-- Validates static, final fields against the
-            expression "^[A-Z][a-zA-Z0-9]*$". -->
-            <metadata name="altname" value="TypeName"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="ConstantNameCheck">
-            <!-- Validates non-private, static, final fields against the supplied
-            public/package final fields "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$". -->
-            <metadata name="altname" value="ConstantName"/>
-            <property name="applyToPublic" value="true"/>
-            <property name="applyToProtected" value="true"/>
-            <property name="applyToPackage" value="true"/>
-            <property name="applyToPrivate" value="false"/>
-            <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|FLAG_.*)$"/>
-            <message key="name.invalidPattern"
-                     value="Variable ''{0}'' should be in ALL_CAPS (if it is a constant) or be private (otherwise)."/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="StaticVariableNameCheck">
-            <!-- Validates static, non-final fields against the supplied
-            expression "^[a-z][a-zA-Z0-9]*_?$". -->
-            <metadata name="altname" value="StaticVariableName"/>
-            <property name="applyToPublic" value="true"/>
-            <property name="applyToProtected" value="true"/>
-            <property name="applyToPackage" value="true"/>
-            <property name="applyToPrivate" value="true"/>
-            <property name="format" value="^[a-z][a-zA-Z0-9]*_?$"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="MemberNameCheck">
-            <!-- Validates non-static members against the supplied expression. -->
-            <metadata name="altname" value="MemberName"/>
-            <property name="applyToPublic" value="true"/>
-            <property name="applyToProtected" value="true"/>
-            <property name="applyToPackage" value="true"/>
-            <property name="applyToPrivate" value="true"/>
-            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="MethodNameCheck">
-            <!-- Validates identifiers for method names. -->
-            <metadata name="altname" value="MethodName"/>
-            <property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="ParameterName">
-            <!-- Validates identifiers for method parameters against the
-              expression "^[a-z][a-zA-Z0-9]*$". -->
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="LocalFinalVariableName">
-            <!-- Validates identifiers for local final variables against the
-              expression "^[a-z][a-zA-Z0-9]*$". -->
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="LocalVariableName">
-            <!-- Validates identifiers for local variables against the
-              expression "^[a-z][a-zA-Z0-9]*$". -->
-            <property name="severity" value="warning"/>
-        </module>
-
-
-        <!--
-
-        LENGTH and CODING CHECKS
-
-        -->
-
-        <module name="LineLength">
-            <!-- Checks if a line is too long. -->
-            <property name="max" value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.max}" default="128"/>
-            <property name="severity" value="error"/>
-
-            <!--
-              The default ignore pattern exempts the following elements:
-                - import statements
-                - long URLs inside comments
-            -->
-
-            <property name="ignorePattern"
-                      value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.ignorePattern}"
-                      default="^(package .*;\s*)|(import .*;\s*)|( *(\*|//).*https?://.*)$"/>
-        </module>
-
-        <module name="LeftCurly">
-            <!-- Checks for placement of the left curly brace ('{'). -->
-            <property name="severity" value="warning"/>
-        </module>
-
-        <module name="RightCurly">
-            <!-- Checks right curlies on CATCH, ELSE, and TRY blocks are on
-            the same line. e.g., the following example is fine:
-            <pre>
-              if {
-                ...
-              } else
-            </pre>
-            -->
-            <!-- This next example is not fine:
-            <pre>
-              if {
-                ...
-              }
-              else
-            </pre>
-            -->
-            <property name="option" value="same"/>
-            <property name="severity" value="warning"/>
-        </module>
-
-        <!-- Checks for braces around if and else blocks -->
-        <module name="NeedBraces">
-            <property name="severity" value="warning"/>
-            <property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
-        </module>
-
-        <module name="UpperEll">
-            <!-- Checks that long constants are defined with an upper ell.-->
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="FallThrough">
-            <!-- Warn about falling through to the next case statement.  Similar to
-            javac -Xlint:fallthrough, but the check is suppressed if a single-line comment
-            on the last non-blank line preceding the fallen-into case contains 'fall through' (or
-            some other variants which we don't publicized to promote consistency).
-            -->
-            <property name="reliefPattern"
-                      value="fall through|Fall through|fallthru|Fallthru|falls through|Falls through|fallthrough|Fallthrough|No break|NO break|no break|continue on"/>
-            <property name="severity" value="error"/>
-        </module>
-
-
-        <!--
-
-        MODIFIERS CHECKS
-
-        -->
-
-        <module name="ModifierOrder">
-            <!-- Warn if modifier order is inconsistent with JLS3 8.1.1, 8.3.1, and
-                 8.4.3.  The prescribed order is:
-                 public, protected, private, abstract, static, final, transient, volatile,
-                 synchronized, native, strictfp
-              -->
-        </module>
-
-
-        <!--
-
-        WHITESPACE CHECKS
-
-        -->
-
-        <module name="WhitespaceAround">
-            <!-- Checks that various tokens are surrounded by whitespace.
-                 This includes most binary operators and keywords followed
-                 by regular or curly braces.
-            -->
-            <property name="tokens" value="ASSIGN, BAND, BAND_ASSIGN, BOR,
-        BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN,
-        EQUAL, GE, GT, LAND, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE,
-        LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN,
-        LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS,
-        MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL, PLUS, PLUS_ASSIGN, QUESTION,
-        SL, SL_ASSIGN, SR_ASSIGN, STAR, STAR_ASSIGN"/>
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="WhitespaceAfter">
-            <!-- Checks that commas, semicolons and typecasts are followed by
-                 whitespace.
-            -->
-            <property name="tokens" value="COMMA, SEMI, TYPECAST"/>
-        </module>
-
-        <module name="NoWhitespaceAfter">
-            <!-- Checks that there is no whitespace after various unary operators.
-                 Linebreaks are allowed.
-            -->
-            <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS,
-        UNARY_PLUS"/>
-            <property name="allowLineBreaks" value="true"/>
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="NoWhitespaceBefore">
-            <!-- Checks that there is no whitespace before various unary operators.
-                 Linebreaks are allowed.
-            -->
-            <property name="tokens" value="SEMI, DOT, POST_DEC, POST_INC"/>
-            <property name="allowLineBreaks" value="true"/>
-            <property name="severity" value="error"/>
-        </module>
-
-        <module name="ParenPad">
-            <!-- Checks that there is no whitespace before close parens or after
-                 open parens.
-            -->
-            <property name="severity" value="warning"/>
-        </module>
-
-    </module>
-</module>
-
diff --git a/gradle.properties b/gradle.properties
index df9bd8a..91b445e 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 group = org.xbib
 name = bibliographic-character-sets
-version = 2.0.0
+version = 2.1.0
 
-gradle.wrapper.version = 6.4.1
+gradle.wrapper.version = 6.6.1
diff --git a/gradle/publishing/publication.gradle b/gradle/publishing/publication.gradle
index c35fcb9..2e2b2c0 100644
--- a/gradle/publishing/publication.gradle
+++ b/gradle/publishing/publication.gradle
@@ -53,12 +53,14 @@ if (project.hasProperty("signing.keyId")) {
     }
 }
 
-nexusPublishing {
-    repositories {
-        sonatype {
-            username = project.property('ossrhUsername')
-            password = project.property('ossrhPassword')
-            packageGroup = "org.xbib"
+if (project.hasProperty("ossrhUsername")) {
+    nexusPublishing {
+        repositories {
+            sonatype {
+                username = project.property('ossrhUsername')
+                password = project.property('ossrhPassword')
+                packageGroup = "org.xbib"
+            }
         }
     }
 }
diff --git a/gradle/repositories/maven.gradle b/gradle/repositories/maven.gradle
new file mode 100644
index 0000000..ec58acb
--- /dev/null
+++ b/gradle/repositories/maven.gradle
@@ -0,0 +1,4 @@
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 62d4c05..e708b1c 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 21e622d..33682bb 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.6.1-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index fbd7c51..4f906e0 100755
--- a/gradlew
+++ b/gradlew
@@ -130,7 +130,7 @@ fi
 if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    
+
     JAVACMD=`cygpath --unix "$JAVACMD"`
 
     # We build the pattern for arguments to be converted via cygpath
diff --git a/gradlew.bat b/gradlew.bat
index a9f778a..ac1b06f 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -40,7 +40,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -54,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -64,21 +64,6 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
@@ -86,7 +71,7 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/src/main/java/org/xbib/charset/PicaCharset.java b/src/main/java/org/xbib/charset/PicaCharset.java
index 245f746..3062562 100644
--- a/src/main/java/org/xbib/charset/PicaCharset.java
+++ b/src/main/java/org/xbib/charset/PicaCharset.java
@@ -101,10 +101,18 @@ public class PicaCharset extends Charset {
         map[0xAD] = '\u01AF';
         /* Modifier letter apostrophe */
         map[0xAE] = '\u02BC';
+
+        // HTML SOURCE = '\u00b4' ?
+        // arab. ALIF? MODIFIER LETTER RIGHT HALF RING?   '\u02be' ?
+
         /* LATIN CAPITAL LETTER A WITH RING ABOVE */
         map[0xAF] = '\u00C5';
         /* Modifier letter turned comma */
         map[0xB0] = '\u02BB';
+
+        // HTML SOURCE =  Grave accent?
+        // arab. AYN? MODIFIER LETTER LEFT HALF RING? U+02BF
+
         /* Latin small letter l with stroke */
         map[0xB1] = '\u0142';
         /* Latin small letter o with stroke */