A detailed description was given by Friedrich Kottler (1914), who formulated the corresponding orthonormal tetrad, transformation formulas and metric (2a, 2b). Also Karl Bollert (1922) obtained the metric (2b) in his study of uniform acceleration and uniform gravitational fields. In a paper concerned with Born rigidity, Georges Lemaître (1924) obtained coordinates and metric (2a, 2b). Albert Einstein and Nathan Rosen (1935) described (2d, 2e) as the "well known" expressions for a homogeneous gravitational field. After Christian Møller (1943) obtained (2a, 2b) in as study related to homogeneous gravitational fields, he (1952) as well as Misner & Thorne & Wheeler (1973) used Fermi–Walker transport to obtain the same equations.