diff --git a/src/external_interfaces_matmul.f90 b/src/external_interfaces.f90
similarity index 98%
rename from src/external_interfaces_matmul.f90
rename to src/external_interfaces.f90
index ad23582..d794e1a 100644
--- a/src/external_interfaces_matmul.f90
+++ b/src/external_interfaces.f90
@@ -1,4 +1,4 @@
-module external_interfaces
+module external_interfaces_matmul
 
    use kinds
 
@@ -108,4 +108,4 @@ end subroutine dgemv
 #endif
    end interface
 
-end module external_interfaces
+end module external_interfaces_matmul
diff --git a/src/formatmul_opts.f90 b/src/formatmul_opts.f90
index 8f79589..6789ff0 100644
--- a/src/formatmul_opts.f90
+++ b/src/formatmul_opts.f90
@@ -250,7 +250,7 @@ end subroutine mm_AB_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mm_AB_2(A, B, C)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), B(:,:)
       real(rk), intent(inout), contiguous :: C(:,:)
@@ -540,7 +540,7 @@ end subroutine mm_ATB_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mm_ATB_2(A, B, C)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), B(:,:)
       real(rk), intent(inout), contiguous :: C(:,:)
@@ -830,7 +830,7 @@ end subroutine mm_ABT_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mm_ABT_2(A, B, C)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), B(:,:)
       real(rk), intent(inout), contiguous :: C(:,:)
@@ -1119,7 +1119,7 @@ end subroutine mm_ATBT_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mm_ATBT_2(A, B, C)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), B(:,:)
       real(rk), intent(inout), contiguous :: C(:,:)
@@ -1411,7 +1411,7 @@ end subroutine mv_Av_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mv_Av_2(A, v, w)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), v(:)
       real(rk), intent(inout), contiguous :: w(:)
@@ -1567,7 +1567,7 @@ end subroutine mv_ATv_1
    !===============================================================================
    !> author: Seyed Ali Ghasemi
    pure subroutine mv_ATv_2(A, v, w)
-      use external_interfaces
+      use external_interfaces_matmul
 
       real(rk), intent(in), contiguous :: A(:,:), v(:)
       real(rk), intent(inout), contiguous :: w(:)