diff --git a/rings.scaladsl/src/main/scala/cc/redberry/rings/scaladsl/Rings.scala b/rings.scaladsl/src/main/scala/cc/redberry/rings/scaladsl/Rings.scala
index 98d5525..cf2c1b3 100644
--- a/rings.scaladsl/src/main/scala/cc/redberry/rings/scaladsl/Rings.scala
+++ b/rings.scaladsl/src/main/scala/cc/redberry/rings/scaladsl/Rings.scala
@@ -580,7 +580,7 @@ object GF {
   * @param cfRingZp64 coefficient ring
   * @param variable   variable
   */
-final case class UnivariateRingZp64 private(cfRingZp64: IntegersZp64, override val variable: String)
+final case class UnivariateRingZp64(cfRingZp64: IntegersZp64, override val variable: String)
   extends AUnivariateRingZp64(rings.Rings.UnivariateRingZp64(cfRingZp64), variable) {
   val modulus: Long = cfRingZp64.modulus
   /**
@@ -597,11 +597,6 @@ object UnivariateRingZp64 {
     * Zp[variable] with specified modulus
     */
   def apply(modulus: Long, variable: String): UnivariateRingZp64 = new UnivariateRingZp64(new IntegersZp64(modulus), variable)
-
-  /**
-    * Zp[variable] with specified coefficient ring (Zp)
-    */
-  def apply(domain: IntegersZp64, variable: String) = new UnivariateRingZp64(domain, variable)
 }
 
 /**
diff --git a/rings/pom.xml b/rings/pom.xml
index bb7b6ca..9883197 100644
--- a/rings/pom.xml
+++ b/rings/pom.xml
@@ -50,6 +50,15 @@
     </scm>
 
     <build>
+        <testResources>
+            <testResource>
+                <directory>src/test/resources/cc/redberry/rings/poly/multivar</directory>
+                <excludes>
+                    <exclude>*</exclude>
+                </excludes>
+            </testResource>
+        </testResources>
+
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
@@ -66,7 +75,7 @@
                     <source>1.8</source>
                     <target>1.8</target>
                     <!--<compilerArguments>-->
-                        <!--<verbose/>-->
+                    <!--<verbose/>-->
                     <!--</compilerArguments>-->
                 </configuration>
                 <executions>
@@ -81,7 +90,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
-                <version>2.4</version>
+                <version>3.0.2</version>
                 <executions>
                     <execution>
                         <goals>