A theoretical approach is proposed for quantitative modeling of SABRE (Signal Amplification By Reversible Exchange) experiments performed at a high magnetic field of an NMR spectrometer. SABRE is a method, which exploits the spin order of parahydrogen (the H$_2$ molecule in its nuclear singlet state) for hyper-polarizing the spins of various substrates to enhance their NMR signals. An important feature of SABRE is that the substrate is not modified chemically: instead spin order transfer takes p...