1. Examples of this kind are the general gas law, pv = RT, and the Bunsen-Roscoe law for radiation effects, It = E, which are approximately obeyed by all the appropriate substances, but accurately by no particular substance
2. Principles of Thermodynamics.;Goodenough,1912
3. Time factor in irradiatio;MacKee;Arch. Dermat. Syph.,1943