It depends on what your teacher requires, but in English classes we usually use MLA format.  This means that you are going to include the line number in the citation.  A citation is basically an acknowledgement of where you go the information.  If you are quoting the poem, you would simply take the line and refer to the poem’s text in your parenthetical citation.

If you are using the enotes text of the poem, this will be your reference.

Silko, Leslie M. "Four Mountain Wolves." Enotes.com. Enotes.com, 2012. Web. 23 Nov. 2012. <http://www.enotes.com/four-mountain/text-poem>.

When you refer to a particular quote, you will simple use the last name (Silko) and then the information or quote.  At the end of the sentence you put the line number in parenthesis.  Here is an example.

In “Four Mountain Wolves” Silko (2012) refers to a “gray misty wolf” (1). 

When you refer to two lines, you can do the same thing and just write (1, 18).  This shows that you used two different lines.