def youngs(v=None, u=None, K=None, L=None, Vp=None, Vs=None, rho=None):
    """
    Compute the Young's modulus of a material given sufficient other moduli.

    :param: v: Poisson's ratio (combine with u, K, or L)
    :param u: Shear modulus (combine with v, K, or L)
    :param K: Bulk modulus (combine with v, u, or L)
    :param L: First Lame parameter (combine with v, u, or K)
    :param Vp: Compressional velocity (combine with Vs and rho)
    :param Vs: Shear velocity (combine with Vp and rho)
    :param rho: Density (combine with Vp and Vs)
    """
    if v and u:
        E = 2*u*(1+v)
    elif v and K:
        E = 3*K*(1-2*v)
    elif v and L:
        E = (L*(1+v)*(1-2*v))/(v)
    elif u and K:
        E = (9*K*u)/(3*K+u)
    elif u and L:
        E = u*(3*L+2*u)/(L+u)
    elif K and L:
        E = 9*K*(K-L)/(3*K-L)
    elif Vp and Vs and rho:
        E = rho*Vs**2*(3*Vp**2-4*Vs**2)/(Vp**2-Vs**2)
    else:
        E = None
    return(E)