To cite the Generic Glass Access Control Model, please use 
 
  Achim D. Brucker and Helmut Petritsch. Extending access control 
  models with break-glass. In Proceedings of the 14th ACM symposium 
  on Access control models and technologies (SACMAT '09). ACM, New 
  York, NY, USA, 197-206. 2009.
  doi: 10.1145/1542207.1542239

A BibTeX entry for LaTeX users is

@InCollection{ brucker.ea:extending:2009,
	abstract  = {Access control models are usually static, i.e., 
                     permissions are granted based on a policy that only 
                     hanges seldom. Especially for scenarios in health care 
                     and disaster management, a more flexible support of 
                     access control, i.e., the underlying policy, is needed.
 
                     break-glass is one approach for such a flexible support of 
                     policies which helps to prevent system stagnation that could 
                     harm lives or otherwise result in losses. Today, break-glass 
                     techniques are usually added on top of standard access control 
                     solutions in an ad-hoc manner and, therefore, lack an 
                     integration into the underlying access control paradigm and the 
                     systems' access control enforcement architecture.

                     We present an approach for integrating, in a fine-grained manner, 
                     break-glass strategies into standard access control models and 
                     their accompanying enforcement architecture. This integration 
                     provides means for specifying break-glass policies precisely 
                     and supporting model-driven development techniques based on such 
                     policies.},
	address	  = {New York, NY, USA},
	author	  = {Achim D. Brucker and Helmut Petritsch},
	booktitle = {ACM symposium on access control models and technologies (SACMAT)},
	doi	  = {10.1145/1542207.1542239},
	editor	  = {Barbara Carminati and James Joshi},
	isbn	  = {978-1-60558-537-6},
	keywords  = {disaster management, access-control, break-glass, model-driven security},
	location  = {Stresa, Italy},
	pages	  = {197--206},
	pdf	  = {https://www.brucker.ch/bibliography/download/2009/brucker.ea-extending-2009.pdf},
	publisher = {ACM Press},
	talk	  = {talk:brucker.ea:extending:2009},
	title	  = {Extending Access Control Models with Break-glass},
	url	  = {https://www.brucker.ch/bibliography/abstract/brucker.ea-extending-2009},
	year	  = {2009},
} 

More details are published in the PhD Thesis of Helmut Petritsch:

  Helmut Petritsch: Break-Glass - Handling Exceptional Situations in Access Control. 
  Springer 2014, ISBN 978-3-658-07364-0, pp. 1-220


A BibTeX entry for LaTeX users is

@PhDThesis{       petritsch:break-glass:2014,
  author        = {Helmut Petritsch},
  title         = {Break-Glass: Handling Exceptional Situations in Access
                  Control},
  school        = {University of Regensburg},
  doi           = {10.1007/978-3-658-07365-7},
  isbn          = {978-3-658-07364-0},
  year          = 2014,
  publisher     = {Springer},
  type          = {PhD Thesis}
}