Janáček created his music theory works, essays and articles over a period of fifty years, from 1877 to 1927. He wrote and edited the Hudební listy journal, and contributed to many specialist music journals, such as Cecílie, Hlídka and Dalibor. He also completed several extensive studies, as Úplná nauka o harmonii (The Complete Harmony Theory), O skladbě souzvukův a jejich spojův (On the Construction of Chords and Their Connections) and Základy hudebního sčasování (Basics of Musical Sčasování). In his essays and books, Janáček examined various musical topics, forms, melody and harmony theories, dyad and triad chords, counterpoint (or "opora", meaning "support") and devoted himself to the study of the mental composition. His theoretical works stress the Czech term "sčasování", Janáček's specific word for rhythm, which has relation to time ("čas" in Czech), and the handling of time in music composition. He distinguished several types of rhythm (sčasovka): "znící" (sounding) – meaning any rhythm, "čítací" (counting) – meaning smaller units measuring the course of rhythm; and "scelovací" (summing) – a long value comprising the length of a rhythmical unit. Janáček used the combination of their mutual action widely in his own works.