Cis-but-2-ene and trans-but-2-ene are stereoisomers with different physical properties, such as boiling points and melting points, due to their distinct molecular geometries. This is a matter of fundamental chemical knowledge and does not require specific paper citations.
The claim is a standard, well-established fact of organic chemistry regarding the physical properties of cis- and trans-isomers (alkenes). Although paper [11] discusses chromatographic differences between cis- and trans-analytes, the statement itself is basic common knowledge that does not rely on contestable evidence or require papers to substantiate.