Institute for Security and Open Methodologies – The Open Source Security Testing Methodology Manual

SANS Whitepaper – Scoping Security Assessments – A Project Management Approach

PCI Data Security Standard – Penetration Testing Guidance

Open Web Application Security Project (OWASP) Top 10

Open Web Application Security Project (OWASP) – Testing Tools

Open Web Application Security Project (OWASP) – Free for Open Source Application Security Tools

Open Web Application Security Project (OWASP) – Testing Guide

FedRAMP – Penetration Test Guidance

The Penetration Testing Execution Standard

ISACA Journal – Planning for Information Security Testing – A Practical Approach