1. Historical maps of land use in Puerto Rico in 1951
- Author(s):
- Helmer, Eileen H.; Córdova, Juan R.; Quiñones, Maya; Hubing, Nick
2. University of Pennsylvania campus tree inventories, 2003 and 2014
- Author(s):
- Roman, Lara A.; Fristensky, Jason P.; Lundgren, Robert E.; Cerwinka, Chloe E.; Lubar, Jason E.
3. Penobscot Experimental Forest historical photo archive: Research and operations from the 1950s through the 1980s
- Author(s):
- Kenefic, Laura S.; Allogio, Jeanette A.; Ziegra, Carolyn G.; Rhodeland, Amelia J.; Anand, Varun A.
U.S. Department of Agriculture