Tekhelet.com , the Ptil Tekhelet Organization ^ Mishneh Torah , Tzitzit 2:1; Commentary on Numbers 15:38. ^ Numbers Rabbah 14:3; Hullin 89a. ^ Exodus 24:10; Ezekiel 1:26; Hullin 89a. ^ Numbers 4:6–12. ^ Kunzler's dictionary of Jazz provides two separate entries: blues, an originally African-American genre (p.128), and the blues form,