Some gems there:
Charles Ives "Some Quarter Tone Impressions" which is listed under Ives, Charles. Here is a great and funny quote from it, which I took the liberty of splitting into two sentences:
"To go to extremes in anything is an old-fashioned habit growing more and more useless as more and
more premises of truth come before man. Though to hold that music is built on unmoveable, definitely
known laws of tone which rule
so as to limit music in all of its manifestations is better-but not much-than
brushing everything aside except ecstatic ebullitions and a cigarette."
Jerry Bergonzi - Vol 4 - Melodic Rhythms.pdf is excellent for thinking about improvising, jazz or otherwise. Bergonzi has a lot of great approaches to improvising.
MusicalInstrumentMakingProjectsFor Children.pdf includes directions for making a slide clarinet
as well as other instruments!
-and-Melodic-Patterns.pdf A classic book.
Wow, and I just noticed the sheet music file at the top- tons of music in there.
Great find, thanks!