Hi Cthoman,
I made these sketches for sale on microstock agencies. But recently i changed my mind. because i don't want to sell  $0.3 per image . I made 3 sketches in one day and 5 more hours to make them color and then sell them $0.3 per image it is insult for all illustrators who is working with this process. that's why i make decision to sell all illustrations if somebody offer me good amount. i have sketches in many categories like, medical, education related, business, finance, etc. i will show them if someone want to see