Don Bluth's Animation School | on Animation". Archived from the original on 2015-12-08 . Retrieved 2017-05-19.

The lead hardness varies with each model, not just the aesthetics of the pencils. The softest is the Matte, followed by the Pearl, 602, and then the Natural is the hardest. I was amazed by the quality of the OPB, but I did feel like the lead was a bit too soft for my everyday rough pencil sketches or even for the entirety of a more finished sketch. The lead was just too soft and easily blended so my hand was often smudging the pencil lines. I think one of the other two pencils would be great for rough sketching or the beginning sketch, before using the OPB to add more depth, through darker shades, to complete the piece. Sondheim, Stephen (2011). Look, I Made a Hat: Collected Lyrics (1981–2011), with Attendant Comments, Amplifications, Dogmas, Harangues, Digressions, Anecdotes and Miscellany. ISBN 978-0-307-59341-2.It is possible to see that the OPB and the Pearl have darker leads than the mechanical pencil and the 602, but only by a fraction! These are just approximations at the leadness based on those from a standard, reliable pencil graphite, like the Mitsubishi Hi-Uni. White, E. B. (2011-10-06). In the Words of E. B. White: Quotations from America's Most Companionable of Writers. ISBN 978-0-8014-6367-9. Cons• The eraser clip is prone to snapping with overuse (although the pencil itself is not affected)

Forum, via Equality (October 9, 2011). "LGBT History Month profile: Composer, conductor Aaron Copland". www.lgbtqnation.com.

Who Makes The Blackwing?

Laurents, Arthur (2001). Original Story by: A Memoir of Broadway and Hollywood. ISBN 978-1-55783-467-6.