diff --git a/main.bib b/main.bib
index cac1400..fa11dca 100644
--- a/main.bib
+++ b/main.bib
@@ -697,6 +697,7 @@
   title        = {Amazonian Linguistics},
   editor       = {Payne, Doris L.},
   publisher    = {University of Texas Press},
+  subtitle     = {Studies in Lowland South American Languages},
   booksubtitle = {Studies in Lowland South American Languages},
   booktitle    = {Amazonian Linguistics},
   keywords     = {classifiers, amazon},
@@ -9410,6 +9411,15 @@ In this paper, I explore some questions about accommodation that often asked. Th
   keywords     = {syntax},
 }
 
+@InBook{Derbyshire1990,
+  author    = {Derbyshire, Desmond and Payne, Doris L.},
+  booktitle = {Amazonian Linguistics},
+  date      = {1990},
+  title     = {Noun classification systems of Amazonian languages},
+  file      = {:/home/noah/Documents/reading/classifiers/derbyshire1990noun.pdf:PDF},
+  keywords  = {classifiers},
+}
+
 @Comment{jabref-meta: databaseType:biblatex;}
 
 @Comment{jabref-meta: grouping: