Process and catalyst for determining nitrogen in {HEAD ~ a sample} according to {TAIL ~ the Kjeldahl principle} 
according to
Process and catalyst for determining nitrogen in { HEAD ~ a sample } according to { TAIL ~ the Kjeldahl principle }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL