Authorization mechanisms for mobile commerce implementations in enhanced prepaid solutions. - Yigang Cai; Jack Kozik; Helmut L. Raether; John B. Reid; Guy H. Starner; Sunil Thadani; Kumar V. Vemuri (Bell Labs Tech. J., 2004)

Subscriber data management in IMS networks. - Daniel F. Lieuwen; Todd C. Morgan; Helmut L. Raether; Satish K. Ramamoorthy; Ming Xiong; Richard Hull 001 (Bell Labs Tech. J., 2006)