You should probably not go beyond thirty minutes, though thirty is the "ideal" length recommended by Alex Osborn.

你大概不会超过30分钟，尽管根据Alex Osborn的建议30分钟是理想的长度。

youdao

Alex Osborn, brainstorming's inventor, recommends an ideal group size of twelve, though this has proven to be a bit unwieldy.

Alex Osborn头脑风暴的发明者，建议头脑风暴的理想人数为12个，尽管这已经被证明有些不实用。

youdao

In the late nineteen-forties, Alex Osborn, a partner in the advertising agency B.

NEWYORKER: Groupthink

Brainstorming is said to have been popularised as a management technique in the early 1940s by Alex Osborn, an American advertising executive.

ECONOMIST: Idea