Update README.md

README.md

@@ -25,7 +25,7 @@ Python 3.6, NLTK and PyTorch 0.4 are required for the current codebase.
 2. Download PTB data. Note that the two tasks, i.e., language modeling and unsupervised parsing share the same model 
 strucutre but require different formats of the PTB data. For language modeling we need the standard 10,000 word 
 [Penn Treebank corpus](https://github.com/pytorch/examples/tree/75e435f98ab7aaa7f82632d4e633e8e03070e8ac/word_language_model/data/penn) data, 
-and for parsing we need [Penn Treebank Parsed](https://catalog.ldc.upenn.edu/ldc99t42) data.
+and for parsing we need [Penn Treebank Parsed](https://catalog.ldc.upenn.edu/LDC99T42) data.
 
 3. Scripts and commands
 
@@ -36,4 +36,4 @@ and for parsing we need [Penn Treebank Parsed](https://catalog.ldc.upenn.edu/ldc
     ```python test_phrase_grammar.py --cuda```
 
     The default setting in `main.py` achieves a perplexity of approximately `56.17` on PTB test set 
-    and unlabeled F1 of approximately `47.7` on WSJ test set.
+    and unlabeled F1 of approximately `47.7` on WSJ test set.