There's also an AGARD "Introduction to Flight Test Engineering", which I have on the shelf at work, but to be honest rarely refer to and unless you get it for free, I'd not bother.
I am not involved in flight testing and I hope you will pardon my intrusion in this forum.
If you are interested, the above mentioned document is available online (free of charge) at:
AGARD-AG-300-14 Introduction to Flight Test Engineering
Other documents from the same source that deal with Flight Testing and Handling Qualities:
AGARD-CP-519 Flight Testing
AGARD-CP-593 Advances in Flight Testing
AGARD-AG-332 Stick and Feel System Design
Reports on PIO
Reports on Flight Testing
I hope this helps.
Aerolearner