On the educational front, Oxford University Press started publishing the "Double Bass Solo" series in 1980. These books are still going strong, and a updated edition of Double Bass Solo Book 1 was published in 2019
Other publications include:
Double Bass Solo Book 2 - popular book of orchestral excerpts.
Double Bass Solo Techniques - This book was published in March 2008.
Subterranean Solos - 9 Concert pieces for Bass and Piano.
Bass Clef Duets - 15 Duets in bass and tenor clefs.
Keith played on a Joseph Panormo (1768-1837) Double Bass, which was featured in "The Strad" magazine of January 1999, and more recently in The English Double Bass book (2018). Click on the link above to read the instrument’s fascinating history dating back to c.1820.