updated readme

Data/README.md

@@ -5,7 +5,8 @@ This folder contains the separate sources used in the paper. The data is organiz
 - `Database/`: Contains the database structure used in the paper and also an abstraction layer for the database. The
   database is a MySQL database.
 - `Utils/`: Contains utility classes used.
-- `Heuristic/`: Contains the heuristic used to map the VCCs to fixing commits.
+- `Heuristic/`: Contains the heuristic used to map the VCCs to fixing commits. The heuristic is adapted from the work
+  of Brack [1].
 - `DatasetSources/`: Contains the dataset sources such as the ground truth data and the scripts used to generate it.
 - `config.xml`: Contains the configuration used to create the mapping database. Read the section below for more
   information.
@@ -44,9 +45,11 @@ A mapping node has to specify a `type` attribute. This attribute has to be one o
 There are other mapping types that are used for mapping ground truth data to the database.
 These are not used for mining and are third party mapping types.
 These are the following:
+
 - **LinuxKernelCVEs:** This type is used for mapping the LinuxKernelCVEs to the database.
 - **PiantadosiApache:** This type is used for mapping the Piantadosi et al. dataset to the database.
-- **VulnerabilityHistoryProject:** This type is used for mapping the Vulnerability History Project dataset to the database.
+- **VulnerabilityHistoryProject:** This type is used for mapping the Vulnerability History Project dataset to the
+  database.
 
 The `<mapping>` node requires at least one `<nvd>` and `<repo>` node
 specifying which CVEs to look into and the source code location.
@@ -62,3 +65,5 @@ evaluated.
 
 This configuration may contain some preliminary mapping approaches for the other projects that may lead to incorrect
 mappings.
+
+[1]: https://github.com/manuelbrack/VulnerabilityLifetimes
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