Discovery

Who's Who?

Professor Bickerton and his three colleagues each have a lab assistant for the summer holidays. The assistants are a great help doing all sorts of things for the harried professors. The problem is that, being post-grad students in white lab coats, they all tend to look alike, so the professors have difficulty telling them apart.

Given the following statements, can you sort out who is helping whom?

If Alice was not assisting Professor Bickerton's observations, Dave was helping that professor.
Dave was not drawing up Professor Bickerton's diagrams if Alice was working with Professor Kidson.
If Carl was not cataloguing Professor Cockayne's specimens, Dave was sorting out Professor Tinsley's slides.
If Dave was typing up Professor Kidson's notes, Bobby was preparing Professor Bickerton's public lectures.
Carl was not doing Professor Kidson's fieldwork if Bobby was not feeding Professor Bickerton's lions.
Carl was checking Professor Bickerton's equations if Dave was cleaning Professor Tinsley's telescope.