Proofreading and indexing.

Maths, business, management, sports, aviation, railways.

M.A. Maths, 25 years working on the business side of a large aerospace company

OUP - Proofreading maths texts
Pearson Education - proofreading and indexing maths texts
answer checking for maths textbooks
various individuals - theses and dissertations

SfEP
SI