Learn English – What preposition do you use with ‘dilemma’

GrammarGirl did a whole post on this. She explains that there is a difference between between and among. She writes:

Here's the deal: you can use the word “between” when you are talking about distinct, individual items even if there are more than two of them. For example, you could say, "She chose between Harvard, Brown, and Yale" because the colleges are individual items.

She goes on to explain that in the following cases, you use the two slightly differently:

Relationships: The Chicago Manual of Style describes these as one-to-one relationships. Sometimes they are between two items, groups, or people, as in these sentences:

• Choose between Squiggly and Aardvark.
• Let's keep this between you and me.

Other times they can be between more than two items, groups, or people as in these sentences:

• The negotiations between the cheerleaders, the dance squad, and the flag team were going well despite the confetti incident.
• The differences between English, Chinese, and Arabic are significant.

On the other hand, you use “among” when you are talking about things that aren't distinct items or individuals; for example, if you were talking about colleges collectively you could say, "She chose among the Ivy League schools." If you are talking about a group of people, you also use “among”:

• Fear spread among the hostages.

• The scandal caused a division among the fans.

• Squiggly and Aardvark are among the residents featured in the newsletter.

Part of a Group: “Among” can also indicate that someone is part of a group or left out of a group, as in these examples:

• He was glad to find a friend among enemies.
• She felt like a stranger among friends.
• Sylvia was later found living among the natives.

From this, you were correct in your use of between. "Cook et. al." formed part of a distinct group of individuals, so you would use between.

Both are possible in speech, although the first is probably more likely. They can be:

a) an inquiry about someone's location;

b) an inquiry about someone's mental, spiritual or emotional state; or

c) an inquiry about which page someone has reached in a book.