@inproceedings{tabassum_shakir_alouini_2012, 
  title={Area green efficiency (AGE) of two tier heterogeneous cellular networks}, 
  DOI={10.1109/glocomw.2012.6477629}, 
  publisher={IEEE}, 
  author={Tabassum and Shakir and Alouini}, 
  year={2012}
  }