diff --git a/pytransform3d/transformations/_conversions.py b/pytransform3d/transformations/_conversions.py
index 8a1d0b61b..ea1c76bd1 100644
--- a/pytransform3d/transformations/_conversions.py
+++ b/pytransform3d/transformations/_conversions.py
@@ -39,7 +39,7 @@ def transform_from(R, p, strict_check=True):
 
     Returns
     -------
-    A2B : array-like, shape (4, 4)
+    A2B : array, shape (4, 4)
         Transform from frame A to frame B
     """
     A2B = rotate_transform(
@@ -70,7 +70,7 @@ def translate_transform(A2B, p, strict_check=True, check=True):
 
     Returns
     -------
-    A2B : array-like, shape (4, 4)
+    A2B : array, shape (4, 4)
         Transform from frame A to frame B
     """
     if check:
@@ -101,7 +101,7 @@ def rotate_transform(A2B, R, strict_check=True, check=True):
 
     Returns
     -------
-    A2B : array-like, shape (4, 4)
+    A2B : array, shape (4, 4)
         Transform from frame A to frame B
     """
     if check:
@@ -126,7 +126,7 @@ def pq_from_transform(A2B, strict_check=True):
 
     Returns
     -------
-    pq : array-like, shape (7,)
+    pq : array, shape (7,)
         Position and orientation quaternion: (x, y, z, qw, qx, qy, qz)
     """
     A2B = check_transform(A2B, strict_check=strict_check)
@@ -143,7 +143,7 @@ def transform_from_pq(pq):
 
     Returns
     -------
-    A2B : array-like, shape (4, 4)
+    A2B : array, shape (4, 4)
         Transformation matrix from frame A to frame B
     """
     pq = check_pq(pq)
diff --git a/pytransform3d/transformations/_dual_quaternion_operations.py b/pytransform3d/transformations/_dual_quaternion_operations.py
index 27a53f95d..16dfebf0c 100644
--- a/pytransform3d/transformations/_dual_quaternion_operations.py
+++ b/pytransform3d/transformations/_dual_quaternion_operations.py
@@ -22,7 +22,7 @@ def dq_conj(dq):
 
     Returns
     -------
-    dq_conjugate : array-like, shape (8,)
+    dq_conjugate : array, shape (8,)
         Conjugate of dual quaternion: (pw, -px, -py, -pz, -qw, qx, qy, qz)
     """
     dq = check_dual_quaternion(dq)
@@ -48,7 +48,7 @@ def dq_q_conj(dq):
 
     Returns
     -------
-    dq_q_conjugate : array-like, shape (8,)
+    dq_q_conjugate : array, shape (8,)
         Conjugate of dual quaternion: (pw, -px, -py, -pz, qw, -qx, -qy, -qz)
     """
     dq = check_dual_quaternion(dq)
@@ -139,7 +139,7 @@ def dual_quaternion_sclerp(start, end, t):
 
     Returns
     -------
-    a : array, shape (8,)
+    dq_t : array, shape (8,)
         Interpolated unit dual quaternion: (pw, px, py, pz, qw, qx, qy, qz)
 
     References
@@ -172,7 +172,7 @@ def dual_quaternion_power(dq, t):
 
     Returns
     -------
-    dq_t : array-like, shape (8,)
+    dq_t : array, shape (8,)
         Unit dual quaternion to represent transform:
         (pw, px, py, pz, qw, qx, qy, qz) ** t
     """