Update README.md

Author: ehsanx

README.md

@@ -39,7 +39,7 @@ simmsm(subjects = 2500, tpoints = 10, psi = 0.3, n = 1000)
 | *n* | Number of simulated datasets an user wants to generate  |
 
 ### Author 
-* Ehsan Karim :octocat: (only R porting from the [SAS](https://cdn1.sph.harvard.edu/wp-content/uploads/sites/148/2012/10/simulate_snaftm.txt) code). Feel free to [report](http://www.ehsankarim.com/) any errors / update suggestions. 
+* Ehsan Karim :octocat: (only R porting from the [SAS](https://cdn1.sph.harvard.edu/wp-content/uploads/sites/148/2012/10/simulate_snaftm.txt) code). I wrote them in R basically to understand the mechanism, but the SAS / SAS IML / Stata codes (I have them as well, available upon request) are faster than this. Feel free to [report](http://www.ehsankarim.com/) any errors / update suggestions. 
 
 ### Original Papers
 - [x] Young J.G., Hernan M.A., Picciotto S., and Robins J.M. [Relation between three classes of structural models for the effect of a time-varying exposure on survival](http://link.springer.com/article/10.1007/s10985-009-9135-3). Lifetime Data Analysis, 16(1):71-84, 2010.