ISBN checksum 10 is encoded as X
diff --git a/Makefile b/Makefile
index 05af9a8..cfcdd81 100644
--- a/Makefile
+++ b/Makefile
@@ -46,6 +46,7 @@
@echo $(patsubst $(SRC_DIR)/%.epub,$(TARGET_DIR)/%.i5.xml,$(wildcard $(SRC_DIR)/*7.epub)) >> $(TARGET_DIR)/filelist$*.txt
@echo $(patsubst $(SRC_DIR)/%.epub,$(TARGET_DIR)/%.i5.xml,$(wildcard $(SRC_DIR)/*8.epub)) >> $(TARGET_DIR)/filelist$*.txt
@echo $(patsubst $(SRC_DIR)/%.epub,$(TARGET_DIR)/%.i5.xml,$(wildcard $(SRC_DIR)/*9.epub)) >> $(TARGET_DIR)/filelist$*.txt
+ @echo $(patsubst $(SRC_DIR)/%.epub,$(TARGET_DIR)/%.i5.xml,$(wildcard $(SRC_DIR)/*X.epub)) >> $(TARGET_DIR)/filelist$*.txt
sed -i -e 's/ /\n/g; /^$$/d' $(TARGET_DIR)/filelist$*.txt
head -n -1 xslt/idsCorpus-template.xml | sed -e 's/{YY}/$*/' > $@
@while IFS= read -r f; do \