diff --git a/README.md b/README.md
index f0fdcaf..01b9e93 100644
--- a/README.md
+++ b/README.md
@@ -56,17 +56,17 @@ there is only one color channel, and thus the size of this dimension is 1.
 
 in alphabetical order, using default `mnists.prepare` arguments:
 
+| subdirectory         | dataset              | train images shape   | train labels shape   | test images shape    | test labels shape    |
+| :---                 | :---                 | ---:                 | ---:                 | ---:                 | ---:                 |
+| [emnist][]           | emnist\_balanced     | (112800, 1, 28, 28)  | (112800, 47)         | (18800, 1, 28, 28)   | (18800, 47)          |
+| [emnist][]           | emnist\_byclass      | (697932, 1, 28, 28)  | (697932, 62)         | (116323, 1, 28, 28)  | (116323, 62)         |
+| [emnist][]           | emnist\_bymerge      | (697932, 1, 28, 28)  | (697932, 47)         | (116323, 1, 28, 28)  | (116323, 47)         |
+| [emnist][]           | emnist\_digits       | (240000, 1, 28, 28)  | (240000, 10)         | (40000, 1, 28, 28)   | (40000, 10)          |
+| [emnist][]           | emnist\_letters      | (124800, 1, 28, 28)  | (124800, 26)         | (20800, 1, 28, 28)   | (20800, 26)          |
+| [emnist][]           | emnist\_mnist        | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
+| [fashion-mnist][]    | fashion\_mnist       | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
+| [mnist][]            | mnist                | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
+
 [emnist]: //www.nist.gov/itl/iad/image-group/emnist-dataset
 [fashion-mnist]: //github.com/zalandoresearch/fashion-mnist
 [mnist]: http://yann.lecun.com/exdb/mnist/
-
-| dataset              | train images shape   | train labels shape   | test images shape    | test labels shape    |
-| :---                 | ---:                 | ---:                 | ---:                 | ---:                 |
-| emnist\_balanced     | (112800, 1, 28, 28)  | (112800, 47)         | (18800, 1, 28, 28)   | (18800, 47)          |
-| emnist\_byclass      | (697932, 1, 28, 28)  | (697932, 62)         | (116323, 1, 28, 28)  | (116323, 62)         |
-| emnist\_bymerge      | (697932, 1, 28, 28)  | (697932, 47)         | (116323, 1, 28, 28)  | (116323, 47)         |
-| emnist\_digits       | (240000, 1, 28, 28)  | (240000, 10)         | (40000, 1, 28, 28)   | (40000, 10)          |
-| emnist\_letters      | (124800, 1, 28, 28)  | (124800, 26)         | (20800, 1, 28, 28)   | (20800, 26)          |
-| emnist\_mnist        | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
-| fashion\_mnist       | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
-| mnist                | (60000, 1, 28, 28)   | (60000, 10)          | (10000, 1, 28, 28)   | (10000, 10)          |
diff --git a/TODO b/TODO
index a3117c3..36a541d 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,5 @@
 TODO
 
- *  add prefixes and links to shape table
-
  *  finish writing README
 
  *  finish npz functionality
diff --git a/mnists/__main__.py b/mnists/__main__.py
index b9f3d8f..4e13aee 100644
--- a/mnists/__main__.py
+++ b/mnists/__main__.py
@@ -1,15 +1,22 @@
 from . import metadata, prepare
 
 
-headers = ("dataset",
+headers = ("subdirectory",
+           "dataset",
            "train images shape",
            "train labels shape",
            "test images shape",
            "test labels shape")
 
-row = "| {:<20} | {:<20} | {:<20} | {:<20} | {:<20} |"
+row = "| {:<20} | {:<20} | {:<20} | {:<20} | {:<20} | {:<20} |"
 
-separators = (":---", "---:", "---:", "---:", "---:")
+separators = (":---", ":---", "---:", "---:", "---:", "---:")
+
+urls = {
+    "emnist": "//www.nist.gov/itl/iad/image-group/emnist-dataset",
+    "fashion-mnist": "//github.com/zalandoresearch/fashion-mnist",
+    "mnist": "http://yann.lecun.com/exdb/mnist/",
+}
 
 print(row.format(*headers))
 print(row.format(*separators))
@@ -18,6 +25,13 @@ for name in metadata.keys():
     # verify every dataset, downloading if necessary.
     # print out the shape table for use in the README.
     data = prepare(name)
-    row_data = [name.replace("_", "\\_")]
+    prefix = metadata[name][0]
+    row_data = [f"[{prefix}][]"]
+    row_data += [name.replace("_", "\\_")]
     row_data += [str(array.shape) for array in data]
     print(row.format(*row_data))
+
+print()
+
+for anchor, url in urls.items():
+    print(f"[{anchor}]: {url}")