As fixed negative 10V voltage regulators are not available you can use the LM7908 (-8V) voltage regulator and add 2.1V zener diode between its COM pin and 0V .. see picture below ..
However, if you can get hands on the LM337 adjustable voltage regulator - with only 2 external resistors - you will be better off than with the LM7908+2.1V zener ..