1. W F Krupke, US Patent No. 6643311 (2001)
2. R H Page, R J Beach and W F Krupke, CMAA1, Proceedings of the CLEO (Baltimore, USA, 2005) p. 467
3. R J Lane, A B Peterson and J Gloyd, CTuD6, Proceedings of the CLEO (Baltimore, Maryland, USA, 2007)
4. W F Krupke, R J Beach, V K Kanz and S A Payne, Opt. Lett.
28(23), 2336 (2003)
5. W F Krupke, Prog. Quant. Electron.
36, 4 (2012)