Finding the original, species description is often the most challenging part of this assignment. You may run into name changes, false leads, dead ends, and other frustrations. That just makes it all the more rewarding when you find it! Think of it like a treasure hunt...
Don't forget about books! The source you're looking for might be hidden within one. You can search print and e-books in the Library Catalog. Since you know the author's name and the year of publication, it's easiest to go that route instead of searching the general Discovery box.
In this case, you would search for the author's name.
You will likely get a lot of hits. However, the filters on the left help you narrow things down quickly. You'll know the general publication year. Then you can limit by call number - Q is science in general, then you narrow get more specific, and so on. Eventually if it's in a book, you'll find it!
