added ref to paper

README.md

@@ -46,10 +46,12 @@ Explanation on how to run NetCore is avilable in the [tutorial notebook](https:/
 Example data for running NetCore is in the data subdirectory.
 
 ### Protein Protein Interaction network
-The CPDB PPI high confidence network [todo add ref] is provided as an edge list.
+The CPDB PPI high confidence network [1] is provided as an edge list.
 The CPDB PPI network can be downloaded via [ConsensusPathDB](http://cpdb.molgen.mpg.de/)
 
 ### Type II diabetes
 GWAS data for Type II diabetes is provided from:
 * [The GWAS Catalog](https://www.ebi.ac.uk/gwas/efotraits/EFO_0001360) - all the gene associations were downloaded and the p-values were converted to weights using -log10.
 * [GWAS list](https://github.com/idekerlab/Network_Evaluation_Tools/blob/master/Data/GWAS_Catalog_genesets.txt) - the genes in this list as known to be associated with Type II Diabetes and can be used as seed genes for NetCore's module identification.
+
+1 [Barel, G., & Herwig, R. (2018). Network and Pathway Analysis of Toxicogenomics Data. Frontiers in genetics, 9, 484.](https://doi.org/10.3389/fgene.2018.00484)