@article{10.1109/SPLC.2006.17,
author = {Ricardo J. Machado, and Alexandre Bragan?, },
title = {Extending UML 2.0 Metamodel for Complementary Usages of the ?extend? Relationship within Use Case Variability Specification},
journal = {Software Product Line Conference, International},
volume = {00},
number = {},
issn = {},
year = {2006},
pages = {123-130},
doi = {doi.ieeecomputersociety.org/10.1109/SPLC.2006.17},
publisher = {IEEE Computer Society},
address = {Los Alamitos, CA, USA},
}