In 1965 Harvey Cohn presented an algorithm for the numerical approximation of low-points for the Hilbert modular group of real quadratic number fields with . It turns out that in fact the low-points correspond to extreme Humbert forms of real quadratic number fields. For extreme Humbert forms we use the theory of Voronoï and Coulangeon for characterization. In this talk we combine the advantages of known algorithms and Cohn's algorithm to obtain new examples of extreme Humbert forms. We are able to compute extreme Humbert forms for the fields , and .