Update README.md

README.md

@@ -24,7 +24,17 @@ The dataset was collected through the PubMed API, based on the names of heart-re
 - **Glossary3 :** [Aiken Physicians Alliance](https://aikenphysicians.com/services/cardiology/cardiology-glossary-of-terms)  
 
 
-### Dataset Field
+# Dataset
+
+## Data Sources
+- **[Pubmed](https://pubmed.ncbi.nlm.nih.gov/)**: PubMed is a database that provides abstracts of research papers related to life sciences, biomedical fields, health psychology, and health and welfare. Among these, we have collected abstracts of papers related to the heart. 
+
+## Keywords Sources
+- **[Scimago Journal & Country Rank](https://www.scimagojr.com/journalrank.php?category=2705#google_vignette)** : We used a list of cardiology-related journals provided by SJR as keywords for data collection.
+- **[National Institutes of Health](https://www.nia.nih.gov/health/heart-health/heart-health-glossary)** : We used a glossary provided by NIH as keywords for data collection.
+- **[The Texas Heart Institute](https://www.texasheart.org/heart-health/heart-information-center/topics/a-z)** : We used a glossary provided by Texas Heart Institute as keywords for data collection.
+- **[Aiken Physicians Alliance](https://aikenphysicians.com/services/cardiology/cardiology-glossary-of-terms)** : We used a glossary provided by Aiken Physicians Alliance as keywords for data collection.
+## Dataset Field
 
 | Field | Data Type | Description |
 | --- | --- | --- |