1. McKesson Specialty Health, The US Oncology Network, The Woodlands, TX, USA
2. Affiliated Oncologists, Chicago, IL, USA
3. Illinois Cancer Specialists, Chicago, IL, USA
4. Southern Cancer Center, Daphne, AL, USA
5. Maryland Oncology Hematology, Columbia, MD, USA
6. The US Oncology Network, The Woodlands, TX, USA