Update README.md

README.md

@@ -28,4 +28,4 @@ Rscript pred.R -i data.rds -o age.pred -a data.age
 If you have any problems about the code and predictor, please contact us: [email protected]
 
 ## Citation
-> Zhang Q, Vallerga C, Walker R, Lin T, Henders A, Montgomery G, He J, Fan D, Fowdar J, Kennedy M, et al: Improved prediction of chronological age from DNA methylation limits it as a biomarker of ageing. bioRxiv 2018.
+> Zhang Q, Vallerga C, Walker R, Lin T, Henders A, Montgomery G, He J, Fan D, Fowdar J, Kennedy M, et al: Improved precision of epigenetic clock estimates across tissues and its implication for biological ageing. Genome Medicine, 2019.