D.P.H. Hasselman ... [et al.]. by D.P.H. Hasselman et al... P.R. Elseman ... [et al.] Gerd Hanselmann ... [et al.]. D.L. Spellman ...[et al.] Mark Kesselman ... [et al.] P.H. Collin ... [et al.]. Bart P. Hartman ... [et al.]. William N. Zelman ... [et al.]. Bret Hartman ... [et al.]