diff --git a/src/crawler/by_source/isrp_crawler.py b/src/crawler/by_source/isrp_crawler.py
index e3e8f7b044fa5e3c4df8b2c1b53202b05b3c47be..1088a450a29c587857e4b5656a4fd347d3a4ed1e 100644
--- a/src/crawler/by_source/isrp_crawler.py
+++ b/src/crawler/by_source/isrp_crawler.py
@@ -18,8 +18,8 @@ class IsrpCrawler(BaseCollectionCrawler):
     source_domain = "ISRP"
     source_website = "https://www.isr-publications.com"
 
-    periode_begin = 0
-    periode_end = 9999
+    delimiter_inline_formula = "\\("
+    delimiter_disp_formula = "\\["
 
     issue_regex = r"Volume (?P<volume>\d+), Issue (?P<number>\d+) pp. (?P<pages>[\d,\-]+) (?:(?P<special>\w+)? )?\((?P<year>\d+).*\)"