diff --git a/R/format_citation.R b/R/format_citation.R
index 3f555e5..2f9267c 100644
--- a/R/format_citation.R
+++ b/R/format_citation.R
@@ -160,15 +160,17 @@ format_citation.data.frame <- function(
         text_list$year <- NA
       }
       # journal
-      if(!is.na(a[[source]])){
-        journal_text <- tools::toTitleCase(tolower(a[[source]]))
-        if(add_html){
-          text_list$journal <- paste0("<i>", journal_text, "</i>. ")
+      if(!is.na(source)){
+        if(!is.na(a[[source]])){
+          journal_text <- tools::toTitleCase(tolower(a[[source]]))
+          if(add_html){
+            text_list$journal <- paste0("<i>", journal_text, "</i>. ")
+          }else{
+            text_list$journal <- paste0(journal_text, ". ")
+          }
         }else{
-          text_list$journal <- paste0(journal_text, ". ")
+          text_list$journal <- NA
         }
-      }else{
-        text_list$journal <- NA
       }
       # authors
       if(any(cols_tr == "author")){
diff --git a/R/screen_topics.R b/R/screen_topics.R
index c651113..0cf6b20 100644
--- a/R/screen_topics.R
+++ b/R/screen_topics.R
@@ -260,7 +260,7 @@ server <- function(input, output, session){
         stop_words = data$stopwords,
         min_freq = input$min_freq * 0.01,
         max_freq = input$max_freq * 0.01,
-        ngram_quantile = input$ngram_quantile * 0.01
+        bigram_quantile = input$bigram_quantile * 0.01
       )
 
       if(input$response_variable != data$columns[1]){
diff --git a/R/screen_topics_ui.R b/R/screen_topics_ui.R
index 7f7ea3d..bfa3291 100644
--- a/R/screen_topics_ui.R
+++ b/R/screen_topics_ui.R
@@ -80,7 +80,7 @@ screen_topics_ui <- function(){
           value = 85
         ),
         sliderInput(
-          inputId = "ngram_quantile",
+          inputId = "bigram_quantile",
           label = "Minimum frequency quantile for recognising bigrams (%):",
           min = 0,
           max = 100,