Propensity scores as a basis for equating groups: basic principles and application in clinical treatment outcome research
Journal of Consulting and Clinical Psychology (2014) - Comment
pubmed: 24708350  doi: 10.1037/a0036387  issn: 1939-2117  issn: 0022-006x 

Stephen G. West, Heining Cham, Felix Thoemmes, Babette Renneberg, Julian Schulze, Matthias Weiler