Update README.md

README.md

@@ -13,7 +13,7 @@ Credits: Kevin Faust & Michael Lee and Colleagues (University Health Network, Ca
 
 ### Introduction
 
-This H&E brain tumor classifier was developed using transfer learning on a histology optimized version of the VGG19 CNN (DOI: 10.1038/s42256-019-0068-6) and trained to recognize the four most common brain tumor types and other surrounding tissue elements.
+This H&E brain tumor classifier was developed using transfer learning on a histology optimized version of the VGG19 CNN [(DOI: 10.1038/s42256-019-0068-6)](https://doi.org/10.1038/s42256-019-0068-6) and trained to recognize the four most common brain tumor types and other surrounding tissue elements.
 
 H&E-stained images patches (dimensions: 1024 x 1024 px) and annotations were taken from previous publicly available datasets (PMID: 35156037). Validation testing was carried out on non-overlapping cases from TCGA.