Michael Katz - Solo Professional Marketing
https://bluepenguindevelopment.com/newsletter-blog/
David A. Fields - Advice for Solo Consultants
https://www.davidafields.com/blog/
Erica Holthausen - Content Marketing
https://www.catchlinecommunications.com/blog
Martin Kadansky - Practical Computer Advice
http://kadansky.com/files/newsletter.html
Kim Gilbert - Small Business Help
https://gilbertbusinessconsulting.com/blog