Practical Free-Space Quantum Cryptography. - Richard J. Hughes; William T. Buttler; Paul G. Kwiat; Steven K. Lamoreaux; Gabriel G. Luther; George L. Morgan; Jane E. Nordholt; Charles G. Peterson; Charles M. Simmons (QCQC, 1998)

Practical four-dimensional quantum key distribution without entanglement. - William T. Buttler; Steven K. Lamoreaux; Justin R. Torgerson (Quantum Inf. Comput., 2012)