diff --git a/Project.toml b/Project.toml
index 7103c41..82170e7 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Groups"
 uuid = "5d8bd718-bd84-11e8-3b40-ad14f4a32557"
 authors = ["Marek Kaluba <kalmar@amu.edu.pl>"]
-version = "0.2.0"
+version = "0.2.1"
 
 [deps]
 AbstractAlgebra = "c3fe647b-3220-5bb0-a1ea-a7954cac585d"
@@ -13,5 +13,3 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
 test = ["Test"]
-
-[compat]
diff --git a/src/Groups.jl b/src/Groups.jl
index 916cc04..a038e99 100644
--- a/src/Groups.jl
+++ b/src/Groups.jl
@@ -233,6 +233,20 @@ end
 #
 ###############################################################################
 
+function AbstractAlgebra.mul!(out::GWord, x::GWord, y::GWord; reduced::Bool=true)
+    resize!(out.symbols, length(x.symbols)+length(y.symbols))
+    for i in eachindex(x.symbols)
+        out.symbols[i] = x.symbols[i]
+    end
+    for i in eachindex(y.symbols)
+        out.symbols[length(x.symbols)+i] = y.symbols[i]
+    end
+    if reduced
+        reduce!(out)
+    end
+    return out
+end
+
 function r_multiply!(W::GWord, x; reduced::Bool=true)
     if length(x) > 0
         append!(W.symbols, x)