- Lapis, E. B., and H. O. S. Valentin. 1979. Field response of ips (Ips calligraphus Germar) to synthetic aggregation pheromones and other attractants . Silvatrop (Philippine Forest Research Journal) 4:223-229.
- Harding, S., E. B. Lapis, and B. Bejer-Petersen. 1986. Observations on the activity and development of Pityogenes chalcographus L. (Col., Scolytidae) in stands of Norway spruce in Denmark. Journal of Applied Entomology 102: 237-244.
- Lapis, E. B. 1985. Geographical and altitudinal distribution of the six-spined engraver beetle (Ips calligraphus Germar, Coleoptera: Scolytidae) in the Philippines . Sylvatrop 10:211-217.
- Lapis, E. B., and H. O. S. Valentin. 1982. Protection of Rhizophora mucronata Lam. seedlings against Poecilips fallax Eggers (Coleoptera: Scolytidae) by cultural methods. Sylvatrop 7: 171-176.
- Lapis, E. 1986. Observations on the seasonal distribution of Ips calligraphus Germar, Baguio City, Philippines . Sylvatrop 11:61-67.
- Lapis, E. 1999. Pest to watch: the ambrosia beetle . Canopy (Philippines) 25:10.