# Compiler cannot find some DX11 types (but can find DX10)?

my problem is probably trivial but I'm new to DX and have some trouble. I've found a code snippet (of a Shader class) with ID3D10Effect and ID3D10EffectTechnique types but I'm using DX11 so I changed these to ID3D11Effect and ID3D11EffectTechnique. But the compiler protested saying that it doesn't know such types. I thought: "maybe there aren't such types actually" but quick google search indicated otherwise. I cannot find any information on which header they're in, though.

So which one is it? I've also found out that there used to be a header called d3dx10math.h but there's no d3dx11math.h. Why is that? Are there any other headers/types abandoned in DX11?