Balasubramanian, D., Narayanan, A., Neema, S., Ness, B., Shi, F., Thibodeaux, R., & Karsai, G. (2007). Applying a Grouping Operator in Model Transformations. In The Third International Workshop and Symposium on Applications of Graph Transformation with Industrial Relevance (AGTIVE). Kassel, Germany. (Original work published October 2007)

Balasubramanian, D., Narayanan, A., Neema, S., Ness, B., Shi, F., Thibodeaux, R., & Karsai, G. (2008). Applying a Grouping Operator in Model Transformations. In Applications of Graph Transformations with Industrial Relevance (pp. 410–425).