1. The Order of Life—Towards a Comparative Biology;Ball;Nature,1981
2. Classes and Cladists;Beatty;Systematic Zoology,1982
3. The Nature of Systematics;Blackwelder;Systematic Zoology,1952
4. Basic Questions of Systematics;Borgmeier;Systematic Zoology,1957
5. Transarctic Relationships and Their Significance, as Evidenced by Chironomid Midges;Brundin;Kunglica Svenska Vetenskaps-Akademiens Handlingar,1966