diff --git a/src/components/Header.vue b/src/components/Header.vue
index c623485f33f6c449745dc58644923f56d5cb0e22..85402414d2428d0f7029c272393d9c3dc7aefc7c 100644
--- a/src/components/Header.vue
+++ b/src/components/Header.vue
@@ -77,7 +77,9 @@ export default {
       let hgnos = []
       this.lemmas.forEach(lemma => {
         let hgint = parseInt(lemma.hgno)
-        hgnos.push(["I","II","III","IV", "V", "VI", "VII", "VIII", "IX", "X", "XI", "XII", "XIII", "XIV", "XV", "XVI"][hgint])
+        if (hgint > 0) {
+          hgnos.push(["I","II","III","IV", "V", "VI", "VII", "VIII", "IX", "X", "XI", "XII", "XIII", "XIV", "XV", "XVI"][hgint-1])
+          }
       })
       return hgnos.join(", ")
     },