The spectra in the library do not need to be complete, i.e. they can involve only wellseparable, easy-to-interpret intervals cut out from the full chemical shift axis. Moreover, the library construction can be further simplified if the user is not interested in estimation for each individual reagent but rather for the product-to-substrate ratio. Note, that this is sufficient to determine the reaction kinetics. In such a case, it is enough to cut out the regions corresponding to products and those corresponding to substrates as a whole without further splitting to individual compounds.