Author-level metrics dependent on time

One of discussable properties of the Hirsch h-index and its related indices, including g-index of Egghe and MAXPROD-index of Kosmulski, is its non-reflection of the time of publication of considered papers. To avoid this failure, we propose and exemplify new time-dependent indices hT, gT, kT, hT, kT andhTT, kTT.