This was adapted from a post on the CALL listserv; many thanks to Sarah Sutherland of CanLII and Ken Fox of the Law Society of Saskatchewan for the information.
There are a couple of ways of noting up a specific paragraph of a case, with the easiest option being on CanLII.
For CanLII, start off by searching for the case you are interested in. Then scroll down to the paragraph and look at the text box to its right. The number in the box will give the number of times the paragraph has been cited. If you then click on that box, that will give you a list of options including “Citing documents”. Clicking on “Citing documents” will take you to a list of cases that cite your paragraph.
To do the equivalent on Lexis Advance and WestlawNext, Ken Fox suggests a phrase search using “a sample of consecutive words in the part of the paragraph likely to be cited, that are (1) distinct enough to not appear exactly as so in any other case and (2) short enough that a search engine can handle it”.