import re


def extract_sentences(modifier, split_text):
    """
    Extracts the sentences that contain the modifier references.
    """
    extracted_text = []
    for sentence in split_text:
        if re.search(r"\b(?=\w)%s\b(?!\w)" % re.escape(modifier), sentence,
                     re.IGNORECASE):
            extracted_text.append(sentence)
    return extracted_text