Guide to IPsec VPNsSheila Frankel, Karen Kent, Ryan Lewkowski, Angela Orebaugh, Ronald Ritchey · First published 2005Open the Tome
Inside Network Perimeter SecurityStephen Northcutt, Lenny Zeltser, Scott Winters, Karen Kent, Ronald W. Ritchey · First published 2002 · Latest edition 2005Open the Tome
