Exponential stability of linear delayed differential systems

Linear delayed differential systems x˙i(t)=−∑j=1m∑k=1rijaijk(t)xj(hijk(t)),i=1,…,mare analyzed on a half-infinity interval t ≥ 0. It is assumed that m and rij, i,j=1,…,m are natural numbers and the coefficients aijk:[0,∞)→R and delays hijk:[0,∞)→R are measurable functions. New explicit results on uniform exponential stability are derived including, as partial cases, recently published results.