Not sure where the author is getting their ventilation rates. ASHRAE 62.2* says
"4.1.1 Total Ventilation Rate. The total required ventilation rate (Qtot) shall be as specified in Table 4-la (I-P) or 4-1b (SI) or alternatively calculated using Equation 4-la (I-P) or 4-1b (SI).
Qtot = 0.03 Afloor + 7.5(Nbr + 1)" (in I-P)
Where Afloor is the floor area and Nbr is the number of bedroom. A 2000 square foot 3 bedroom house would be 90cfm or ~45L/s.