“…The first inspiration for the presented series of articles (some of them are joint works with Hegedűs and Ossowski) was the publication [20] of professor Nowicki and professor Moulin Ollagnier. The fundamental problem investigated in that series of articles concerns rings of polynomial constants ( [26], [28], [33], [29], [8]) and fields of rational constants ( [30], [31], [32]) in various classes of cyclic factorizable derivations. Moreover, we investigate Darboux polynomials of such derivations together with their cofactors ( [33]) and applications of the results obtained for cyclic factorizable derivations to monomial derivations ( [31]).…”