Better cite Kirk & Anna 2017 to document project start

Change-Id: I6bcb49ab3d6b1839c07a6b5289e9acd5a124806a
diff --git a/R/poster.Rmd b/R/poster.Rmd
index 8feea6b..56703b9 100644
--- a/R/poster.Rmd
+++ b/R/poster.Rmd
@@ -87,7 +87,8 @@
 source("common.R")
 ```
 # ICC aims & charcteristics
-* make available comparable corpora  of many languages for contrastive linguistic research [@cermakova_international_2021]
+
+* make available comparable corpora  of many languages for contrastive linguistic research [@kirk_ice_2017]
 * mostly based on existing corpora
 * ICC has a pre-defined “balanced” composition
   * based on the one of the ICE [@greenbaum_comparing_1996]