Weekend combinatorics

Summary:
Thinking of spending an extended weekend at his summer residence, yours truly wanted to take five of his favourite books with him. On my bookshelf are five books by Strindberg and four by Shakespeare. I thought of bringing with me at least two of the Strindberg volumes. In how many ways can I do this?

Topics:
Lars Pålsson Syll considers the following as important: Varia

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