Update README.md

 # Sentence simplification with iSimp and Daniel Gutiérrez's algorithm
 
+## About iSimp
+We employ iSimp available in https://research.bioinformatics.udel.edu/isimp/
+Peng,Y., Tudor,C., Torii,M., Wu,C.H., Vijay-Shanker,K. (2012) iSimp: A Sentence Simplification System for Biomedical Text. In Proceedings of the 2012 IEEE International Conference on Bioinformatics and Biomedicine. 211-216.
+
 ## Directories 
 ### iSimp
 ```Shell
@@ -35,7 +39,7 @@ Usage: ./sentence-simplification-main.sh <input_path> <output_file_path>
 ./sentence-simplification/sentence-simplification-main.sh ./format/split_sentences ./algorithm_sentences/filename.txt
 <input_path> Path for cleaned and separated sentences, one per file.
 <output_file_path> Path and filename. It uses filename to create files with simplified sentences and with an index within the filename.
-**Requirements**: senteces must be separated one per file and they must be cleaned.
+**Requirements**: sentences must be separated one per file and they must be cleaned.
 It calls simplifier.py
 ```
 ### Python scritp for sentences simplification