Independent personal services: taxable in resident state unless fixed base or 183 day presence allows source-state taxation of earned income. Income from independent personal services of a resident is taxable only in the State of residence, except where the individual has a fixed base in the other State-then only income attributable to that fixed base may be taxed there-or where the individual's stay in the other State meets or exceeds 183 days in any twelve-month period, in which case only income from activities performed in that State may be taxed there.