citations - What's the correct way to cite a paper cited by another paper?

The example is when you might be reading a certain paper, and the authors refer to another paper. You can't get that other paper as it's unpublished, or it's in a language that you can't read, or maybe something else.

My guess is:

Featherstone et al 1900 (in Thomas and Cullen 2002).

And how is it to be handled in the bibliography?

Answer

In APA style, you can write, (e.g., see this APA tutorial)

Featherstone et al 1900 (as cited in Thomas and Cullen 2002)

Of course, in general you should try your best to read the original and cite the original directly.

Someone in the comments asked:

"In such case do I need to list original paper also in reference section or only the recent one I am referring to?"

The reference to the original article is the more important reference to include, but you should include both in your reference list.